S1 lines and M lines on an invoice


When I do a customer product invoice, if I use the S1 product code but it is a zero value invoice, how do I get it to show 0.00 as the unit price without it affecting the M lines which do not have any value?

If I untick "supress if zero" then I end up with 0.00 values on my M lines as well as my S1 lines.

Never has this issue until V30!

thanks in advance