Hello, m0n0wall users

I read m0n0wall hack guid and follow URL
http://m0n0.ch/wall/list/?action=show_msg&actionargs[]=1&actionargs[]=46
http://jief.theroux.ca/docs/custom-m0n0wall-howto.txt

But I can't find about memory file system.

On m0n0wall, how to increase memory filesystem?

Default memory file system size is about 6MB, I need more space 

Have a nice day~