USEREXIT FOR vf01 TRANSACTION IN INTER COMpany billing

Hi guys ,

Could you please suggest a closest userexit for Intercompany billing where the requirement is It should take iv billing type automatically before pgi is done.one sap note is applied which is allowing billing to take place with out pgi ,but we have to select manually ,the requirement is it should propose automatically.Please help.

Regards

vinod sunkari