Using SDK doesn't always work. When I tried it, I managed to move most apps to the SD card (that I previously could not), but the internal space did not increase as expected!
For example I moved a 3MB app and my internal space only increase by 0.2MB.
I've also noticed that when some moving apps to the SD card normally (using an apps2SD app downloaded from the Market), it does not move the whole app just a percentage of it (the percentage various).