Filtering error - report Request page

Hi everyone,

I tried to run report 109 with a filter on "Payment terms" in the request page like this:1M(8D).
I got the following error message:

One or more filters are not valid. Check the filters and correct them as needed. The filter "1M(8D)" is not valid for the Payment Terms Code field on the Customer table. Did not expect a '('.

Is standard NAV really unable to handle such filters for Code fields?

Thanks in advance