Hi,
I have Quicken 2003 (not 2004). However, I think this simple workaround may work on 2004 as well. Install and register Quicken on Windows (for those of you who still have a Windows environment). Copy qwrs.dat file from windows to the corresponding linux directory where Quicken is installed and bingo - online features work, without the annoying registration dialog popping up.
BTW - I have put some recent updates in the Tips&Tricks tab for Quicken 2003 - some of these might work in 2004, so check 'em out.