I have modified the script so it also moves the dalvik cache to your SD card. I recommend to use at least class 4 SD card for this. I have attached the modified script. Follow the instructions from the original thread but use the files from my attachment. For me it works fine.If you have any problems please share so we can try to fix them together.
And finally using both the original and modified app2sd you CAN normally use your sd card as mass storage device.