just finished doing this right now.. works fine..

one thing
# sfdisk /dev/mmcblk0 <-- this is one command

then it says loads of crap
then you'll be at a prompt like:
/dev/mmcblk0p1:

then you put in 1,15000,6
another thing.. this is where you set how big you want each partition
SO if you have a 2gb card, you're giving 1.5gb to the OS.
Which is TOTALLY unnecessary.
the 15000 is the size of the partition for the 'Memory Card'
whatever size you make this is how big the device will say your memory card is.
the rest will go to the OS, for installing programs and the OS itself.
for my 2gb card i used 1,45000,6 and got over 300mb for proggys and 1.37gb for the memory card.
just make sure you change the second set to whatever you put in the first PLUS ONE.
so if you did:
/dev/mmcblk0p1:1,45000,6
THEN
/dev/mmcblk0p2:45001,,
THEN leave mmcblk0p3 and 4 blank.