mcogilvie is correct. The extra fields added by the add-in won't carry over to the Palm even with additional software such as PocketMirror.
What I do is give each project a unique id: @X04 or @P03 that I put at the beginning of each subject. (I use 4 different alpha characters for the second byte): P for Prospects, C for Clients, S for Support and X for Other).
I put three exclamations marks at the beginning project task itself. Such as @C03 !!!Client analysis project. This allows that task to be sorted at the top of the list.
If I enter a new project-related task, I use this convention and then periodically go to Outlook and check to see if I have any tasks beginning with @... that don't have the Project field populated.
All of this has become much more useful with the release of DateBk6 on the Palm OS which allows lots of customization for todo sorting.