I think you should not use it in this case. But in general:
Internal memory (eMMC) is 27GB has Fat32. If you will change it on ext3 or ext2 you will not have size limit. But this memory will be unavailable from windows machine.
Exist several ways to do it. Some of them simple some of them not....
see this thread for details: http://talk.maemo.org/showthread.php?t=37869&page=9

I personally just reformat /home/user/MyDocs to ext3 and modified ke-recv package