Validation: How to maintain the entry in GB02C

Question

HI FI GURUS n EXPERTS,
My requirement is that - We want to restrict Negative posting for some GL i.e. For some GL balance should not be Zero.
When I have made the search on SDN, I found it can be done with the help of Validation: OB28 & GGB0.
Currently we are not using any validation. When we use T-Code GGB0 --> Financial Accounting --> Line Item --> New Validation
System shows a pop-up window to select Boolean Class & Message ID.
I also found that this information is maintained in Table GB02C.
When I use Se16 to see the detail of the table GB02C, I found there is only one entry Bool. Class: FP1 & Message ID 7F.
But I don't know How to maintain the entry in table GB02C & What is the T-Code for it. which message ID I have to create.
Please help.
DSC

Answer 1

Dear Alex,
When I use: GGB0 --> Financial Accounting --> Line Item --> New Validation
System shows a pop-up window to select Boolean Class & Message Class, I select the Message Class 9 and for Message Class Press F4 and select any message class. System gives an error message: Message ID must start with 'Z' Message no. GB116.
Basically, My question is that: Which T-Code we have to use to maintain Boolean Class & Message Class.
With thanks,
DSC