Don't know. I use the external SD for media files. You know, a throw back to the cassette days.
All my apps I put into the internal memory.
Go to settings>Applications>Manage applications.
When you get there, you'll see the list of apps with check boxes next too them.
On top of the list are 4 options:
Maybe, by checking an app in the USB storage option you'll be able to transfer them.
Edit: Just moved one. No need to do much, when you tap on "manage applications" and get to the list, tap on the app you want to transfer. It will show all the app info and some buttons like "force stop ","uninstall","clear data" and (the one you want) "move to USB Storage".
Expert or novice, you should be able to take it from there.
Pinged from Newark NJ, to Fort Worth Texas.