OSS note 38501 is not working

Hello All ,

We have implemented note oss note 38501,( It is a userexit SAP is recommending to avoid F2 invoice generation before IC invoice generation ) . While testing the changes we found that exit is not triggering from tcodes: VF01,VF04 and still system is creating F2 invoice first . Please help if you have any suggestions .

Regards,

Greeshma