SL-5500 Memory Limits?

Hi!

This is a bit of a Newbie question, so apologies if I should have posted it elsewhere.

I've just bought a second-hand SL-5500 with a 64MB SD card and a 32MB CF card.

I would like to expand the system memory/storage considerably but I'm not sure what limits there are on the size of SD/CF memory I can use. I don't want to spend lots of money on cards if (a) the Z can't use them at all or ( the Z can only address a small part of them.

I contacted Sharp Service and was told that the limits are 128 and 192 for SD RAM and CF RAM respectively. I presume that these figures are in MB and only apply to memory (RAM/ROM) rather than storage (disk) devices.
However, this doesn't seem to stack-up with various comments I've read on the ZUG mailing lists and other places, which seem to indicate that people are using up to 1GB SD card and 512MB/1GB CF cards and also using up to 4GB CF microdrives.

Is there a FAQ somewhere which details what the limits are (if any) and what devices do/don't work with the Z?

Many thanks in advance,

John (slightly confused but fascinated with the idea of Linux of a handheld!)