Painfully slow login to AD bound Leopard machine when off home network

Dear all Just looking for a little help with this problem that seems to trip a lot of people up and is causing me no end of grief. I have a number of fully patched Leopard machines that are bound to my AD (Server 2003). When on the home network, logging in seems swift and works as expected. When users take the machines off site, login can take 5 minutes or more. The user adds correct credentials but the desktop does not appear for a very long time. When I have tried logging in using a local Admin account, switching off Airport and then logging in using an AD account, login is once again swift again. It all seems as if Leopard is finding a suitable wireless network, spending far too long looking for the Domain before eventually giving up and using the cached credentials instead. I have read that disabling Bonjour on the machine will stop this problem (i have not yet tested) http://www.macwindows.com/leopardAD.html#111607z ...but I am reluctant to use this "Solution" as I would like to be able to use Bonjour on the local network as well as having AD-bound machines. However, is disabling Bonjour really the only answer? Is there not some time-out setting somewhere that could be amended to stop Leopard spending forever looking for home? Any help would be very gratefully received Thanks Gordon