Ux50 Memory Stick

I want to buy larger capacity memory for my Sony Clie PEG-UX50.  I've read about the issues Memory Stick's have with the UX50 and the library update download, MSUPDATEMODULEUX102.PRC.  The Sony website says that the MSX-1GS (1GB) has no known problems with the UX50.  Is that correct?  Can I buy a MSX-1GS MS and expect it to work correctly in the UX50?  Is a 2GB MS available for the UX50 with no known problems?  If a 2GB will work, what model number do I buy?  Thank you.