Complex Payment Term Calculation

Hello,

I have the following request on a payment term and I am not able to set it correctly in IFS, version 9.

The Due Date calculation should be : 30 days from 10th of the Next Month.

For example, if my invoice date is 15th of September, the Due Date should be  calculated as  30 days from 10th of October: which is 9th of November.

I tried the following  option but it is not working properly:

With this setup is calculating first 30 days from the invoice date, then it goes to the next month( due to End of Month-Due Date checkbox) and sets the final due date to 10th of next month. 

I can not get a way of calculating the Due Date starting from a specific date.

Specific Due Day field is the latest one taken into account in the calculation, so I was not able to add any days to that specific date.

Did you have a similar case in your projects? How did you manage it?

Thanks for your help,

Ioana