FIN AP 9.1 after Bundle #8, new Positive Payment File Process, is there any documentation?

Our bank requires a specific format for our Positive Payment file.  We just applied MP5 (which includes Bundle #8) to our Development environment and we now see that the Pos Pay file is created using a new Application Engine process, AP_APY2055 and not the delivered POS1.RPT file.  In the past it was simple to customize your own POSx.RPT file to be created.  Now it appears we must customize the Application Engine program to write out the file differently than what is delivered.  Is there any documentation discussing the new application engine?  I've reviewed it briefly and cannot see anything showing a simple