Setting limits

[Digger57]

I installed my DG-380, along with a Triax 90cm dish and an Inverto Scena 5 IDL 5550S CI Receiver and it runs great. Right now I haven't set the limits and it happened one time, when I was fine-tuning the dish azimuth with the receiver commanding the motor, all of a sudden the motor kept on turning east until it hit the eaves (no damage to the dish or the motor by the way). I don't want that to happen again, so I want to set the limits.But how do I do this. I'm afraid of ruining my calibration.
When I use the receiver to turn the motor to its east/west limits, it's turning back to the chosen satellite and gives me no chance to set the proper limits.