As we get all of the platforms switched over to having both php4 and php5, we'll need for the pear module to know about both. While I'm not exactly clued in about how Pear works, I do know that we end up with two binaries. One is pear (for whichever php is the system-default) and the other is pear4|5 (depending on which php is provided by our package). Seems like we probably need to have two modules (which I think can be identical, but labelled differently...like "Pear for PHP 4" and "Pear for PHP 5". The locations are a little bit different depending on which OS and version.
You're better equipped to know how we ought to go about that. Holler if you have any questions about paths in our custom php/pear packages.