We have a large application that we market to people that is written in VFP 9 SP1. We have a need to modularize some of the functionality. Specifically, to deal with PCI PA-DSS compliance, we want to isolate all of the credit/debit card processing functions into a separate module that can be versioned separately from the rest of our software and distributed as a separate file, be it a dll, exe, ocx, or whatever. This module needs to be able to support displaying data entry/progress screens as well as returning transaction results to the calling program.

What would be the best way to do this? I would like it to appear seamless to the end user, i.e. no separate entry on the taskbar for any windows it brings up, I would like any windows displayed to be clients of the main application window, etc.

Has anybody done anything like this for a VFP application? Is VFP the right tool to create this module in?

Thanks in advance for your help.