The TiltSensor class was originally written for the mindsensors version of the Acceleration sensor.
It should work for the HiTechnic sensor as well. It returns an 8-bit value using registers, 0x42, 0x43 and 0x44. For the HiTechnic sensor, you can get an extra 2 bits of precision by reading registers 0x45, 0x46 and 0x47 - see the C code on the HiTechnic site.
If you need this you can call getData to get one byte at a time, or all 6 in one go if you prefer.
As I understand it, there is no difference between Tilt and Acceleration values - they are the same thing. We called it TiltSensor as the name is shorter.