How to set Validation for mandatory Settlement rule for WBS

Dear All,

I have a specific requirement in my project.

we have here 2 types of project profile.

In one profile my requirement is to maintain settlement rule on WBS level before start execution.

While trying to set validation, m not able to get the required table in table fields for settlement rule.

Please let me know what is the right method to adopt that ??

Actual requirement :

While try to set user status : EXEU, system will pop message for mandatory settlement rule at WBS level.

Thanks & Regards,

Narender