Here is a (slightly altered) quote from windirt (the EZTeam rep on the US forums) regarding the usage of the expansion, hopefully it should clear up some issues.
1. Rumble PAK function
Support all official rumble enabled games.
You have to place the newest official savelist into shell folder to make rumble pak works properly. This is because we marked the rumble enabled game in the list.
you can download the list here (various forum members make their own lists and tools and it should be incorporated somepoint soon as well):
http://www.ezflash.cn/zip/ezsave.zip
(the following paragraph is perhaps not of much interest to most end users)
Manual mark the rumble enabled game in savelist.
open ezsave.lst by a hex editor, each game used 20 bytes to store game name, savetype, rumble status or another thing.
the first 16 are the rom name (directly from the rom but it is also a combination of the internal name and serial)
17th byte is savetype.
18th is the rumble status: set it to 01 enable the rumble, 00 to disable.
Vibration strength has 3 levels of adjustment in main menu by press L+R
2. Browser RAM Expansion function
Just copy the Browser cleanrom to microsd, or patch it with hybrid tool if you have a slow card. (bear in mind the browser uses standard PC formats for much of the internals so you can hack to suit your needs).
3. GBA function
Please use EZ4Client transfer GBAROM to microsd because the GBAROM still need be patched to save properly. It can't work or save properly if you direct copy them to microsd, the "saver" folder which EZ4Client auto generates can be deleted however.
1.Write GBA game
Highlight the GBAROM which you want to write and press R+SELECT. A to confirm, B to cancel
2. Backup Save from expansion card
Press R+X on EZ5 desktop, the saver will be saved to the GBASAVE folder. the file name is the ROMTITLE.sav. ROMTITLE is the current one written on expansion, A to confirm, B to cancel
3. Write the save to expansion card
Highlight the save file which you want to write in GBASAVE folder, and press R+Y, A to confirm, B to cancel
4. Launch the GBA game
Just press R+A