service tax reg.no.

Hello,

I have a query regarding service tax. We have sales commission agents not having service tax registration numbers and they say they are below the limit prescribed for service tax registration.But we say to them that they may be serving other than us also.so we are going to request them to give us a declartaion that their gross receipts do not exceed the limit prescribed  under service tax for registration in writting.

Whether it is the correct step , if so how the declaration formate should look?

Ravi