What do the characters look like? Not what they're supposed to look like, but what is being shown.
I'm currently working on the Parallax LCD and my custom chars were messed up also. the bit patterns were backwards for one thing, plus I can't seem to send a nul character to the display mySerial.write(0); doesn't work but because the LCD only uses 5 bits to make the char; I did a mySerial.write(32); instead.
Winston