how to write error log while creating invoice and avoid implicite commit

Hi,

I've have written code in exit RV60AFZZ in which I check for some possible errors while invoicing via VF01/VF04. If conditions are met then we create error message and display it to the user. As result we had a lot of missing SD invoices in FI when we did batch/mass invoicing. I've opened OSS note and SAP support team wrote that using statement MESSAGE is forbidden in UE. It can lead to implicite commits.

Do you have some example how to write error log for invoincing in VF01/VF04 transactions?

Thanks