If the lifting arms are anything like on the D-4 (well, the D-4 arms that fit to the dichroic head) and you have a hex key of the right size (Omega specified a "#10 allen key", and I found that a Torx T-10 bit fit perfectly), you can loosen the two set screws on an end of each arm and pull out the shafts. If I have the right idea of your problem, that should allow you to lower the carriage and then you can put the lifting arms back. I've attached a picture of the set screws in question. My arms have two each. Loosen them and you should be able to pull the arm off the shaft, which you can then slide out of the carriage.
Note that doing this will upset the alignment of the lifting arms on each side, but it's very easy to realign (and not nearly as critical as e.g. the lens alignment).