REST API: Manual Supplier Invoice - SUP_TAX_MANDATORY: A Tax Code is required...

Is there a full example on how to create a Manual Supplier Invoice using the API? If not, here’s my attempt:
 

1. Get Token:
   • https://[root].cloud/auth/realms/linmcfg1/protocol/openid-connect/token
2. Post Header:
   • https://[root]/main/ifsapplications/projection/v1/ManualSupplierInvoiceAssistantHandling.svc/ManSuppInvoiceVirtualSet
   • Body:   

     •  {
          "Company": "001",
          "AffLinePost":false,
           "AdvInv":false,
           "ProposalExist":false,
           "PostPrelTaxWith":false,
           "PrepayBasedInv":false,
           "UseProjAddressForTax":false,
           "SiiProposal":false,
           "AboveTaxControlLimit":false,
           "EinvoiceSent":false,
           "UseDeliveryInvAddress":false,
           "ExcludePostingAuth":true,
           "CurrDifferenceInvoice":false,
           "CPeriodicInvoice":false,
           "PrepayBasedEnabled":"FALSE",
           "InvoiceNo":"INV-10042",
           "Identity":"10042",
           "InvGrossCurrAmt":250,
           "Currency": "CAD",
           "CurrRate":1,
           "AuthId":"*",
           "DueDate":"2025-08-10",
           "InvoiceRecipient":"*",
           "TaxCurrRate": 1.3718,
           "PayTermId": "0",
           "DivFactor":1
        }

3. Post Invoice Line:
   • https://[root]/main/ifsapplications/projection/v1/ManualSupplierInvoiceAssistantHandling.svc/ManSuppInvoiceVirtualSet('3B2587DDEC9283BDE063A478EF0AA2EA')/ManSuppInvoiceItems
   • Body

     • {
         "ParentObjkey": "3B2587DDEC9283BDE063A478EF0AA2EA",
         "Company": "001",
       
         "ItemId": 1,
         "CurrCode":"CAD",
         "CurrRate":1,
         "NetCurrAmount": 221.24,
         "Creator":"JSMITH",
         "Identity":"001",
         "PartyType":"Supplier",
         "DivFactor":1,
         "TaxCodeRef":"1"
       }

4. Posting Lines
   • https://[root]/main/ifsapplications/projection/v1/ManualSupplierInvoiceAssistantHandling.svc/$batch
   • content-type: multipart/mixed; boundary=42d4c04e-78b3-448c-b5b3-de6ff7df35e8
   • Body (raw)

     • --42d4c04e-78b3-448c-b5b3-de6ff7df35e8
       Content-Type: multipart/mixed;boundary=138bf85c-46b4-48bd-9300-12bde713fe50
       
       --138bf85c-46b4-48bd-9300-12bde713fe50
       Content-Type: application/http
       Content-Transfer-Encoding:binary
       Content-Id: 1
       
       POST SaveCheckOk HTTP/1.1
       Accept:application/json;odata.metadata=full;IEEE754Compatible=true
       Content-Type: application/json;IEEE754Compatible=true
       
       {"Init":true}
       
       --138bf85c-46b4-48bd-9300-12bde713fe50
       Content-Type: application/http
       Content-Transfer-Encoding:binary
       Content-Id: 2
       
       POST ManSuppInvoiceVirtualSet(Objkey='3B2587DDEC9283BDE063A478EF0AA2EA')/ManSuppInvoicePostingsArray?select-fields=PeriodAllocSeq,CurrAmount,DomAmount,CodeA,VoucherDate,Company,InternalSeq,Identity,InvoiceId,ItemId,VoucherType,CurrRate,DivFactor,ParallelCurrRate,ParallelDivFactor,RowId,CurrCode,AddInternal,ProjectId,Objkey,InvoiceNo,PeriodAllocAccount,CodeB,CodeC,CodeD,CodeE,CodeF,CodeG,CodeH,CodeI,CodeJ,Quantity,ProjectActivityId,WoNo,WorkTask,PostingType,VoucherCompany,NetCurrAmount,LineRef,OptionalCode,ParentObjkey,ProjectCodePart,Text,RequiredString,AutoPostingProcCode,OrderNo,CurrAmountDebit,CurrAmountCredit,DomAmountDebit,DomAmountCredit,ThirdAmount,ThirdAmountDebit,ThirdAmountCredit,NonDeductTaxCurrAmount,CurrAmtDummy,luname,keyref HTTP/1.1
       Accept:application/json;odata.metadata=full;IEEE754Compatible=true
       Content-Type: application/json;IEEE754Compatible=true
       X-IFS-Accept-Warnings: false
       
       {
         "ParentObjkey": "3B2587DDEC9283BDE063A478EF0AA2EA",
         "Company": "001",
         "CodeA": "0000001",
         "Identity": "00001",
         "PartyType": "Supplier",
         "CodeB": "00001",
         "CodeC": "00",
         "OptionalCode": "HST",
         "CurrAmount": "221.24",
         "DomAmount": "221.24",
         "CurrAmountDebit": "221.24",
         "DomAmountDebit": "221.24",
         "Text": "SOME SUPPLIER- CAD",
         "PostingType": "MANUAL",
         "VoucherType": "I",
         "VoucherDate": "2025-07-17",
         "UserGroup": "AC",
         "Reference": "MANUAL",
         "VoucherCompany": "001",
         "AddInternal": false,
         "LineRef": "1",
         "CurrCode": "CAD",
         "CurrRate": "1",
         "DivFactor": "1",
         "Spend": false,
         "InvoiceRecipient": "JSMITH",
         "RequiredString": "M;K;K;S;S;K;S;S;S;K;K;K;N;"
       }
       
       --138bf85c-46b4-48bd-9300-12bde713fe50
       Content-Type: application/http
       Content-Transfer-Encoding:binary
       Content-Id: 3
       
       POST SaveCheckOk HTTP/1.1
       Accept:application/json;odata.metadata=full;IEEE754Compatible=true
       Content-Type: application/json;IEEE754Compatible=true
       
       {"Init":false}
       
       --138bf85c-46b4-48bd-9300-12bde713fe50--
       --42d4c04e-78b3-448c-b5b3-de6ff7df35e8--
       

5. Finish Invoice
   • https://[root]/main/ifsapplications/projection/v1/ManualSupplierInvoiceAssistantHandling.svc/FinishInvoice
   • Body

     • {
           "Objkey":"3B2587DDEC9283BDE063A478EF0AA2EA",
           "Identity":"00001",
           "UpdateHeader":false,
           "IsZeroInv":false
           }

   • FAILS WITH:

     • {
           "error": {
               "code": "DATABASE_ERROR",
               "message": "Database error occurred. Contact administrator.",
               "details": [
                   {
                       "code": 20110,
                       "message": "ORA-20110: TaxHandlingUtil.SUP_TAX_MANDATORY: A Tax Code is required when supplier tax validation has Transaction Level selected on Company, Tax Control tab."
                   }
               ]
           }
       }

Everything works fine until step 5 (finish the invoice), it asks me for a taxcode

I don’t know the field I must use, there is TaxId, but it only accepts numeric values and I don’t know where to get those from, so I can’t just put “HST”, any help is welcome