Michael, in the MEM setup area, go to the section titled "Disable Account Substitution". I suspect that you have the AP account substitution disabled; simply uncheck that box and the entity segment will sustitute properly on both the expense and AP accounts. If you can't find it, email me at neil@binarystream.com and I will find some time to assist you.
Neil MacDonald
Solutions Consultant
Binary Stream Software
604 522 6300 ext 106
neil@binarystream.com