USB RAM PIC18F14K50

Hello,

I have a question regarding the USB RAM of my PIC18F14K50. In the 
datasheet it says, that there is a 256byte big USB RAM (see attached 
file). So for my USB transfer, can I only send data up to a size of 
256byte (less the size which is used for descriptors etc...)? Do I have 
to use this stack for USB sending or can I store my data elsewhere on 
the PIC and send it from there? (I tried that but it didn't seem to 
work...).

So can someone please clarify how I have to deal with this USB RAM?
Thanks very much!

Regards, lh