Well,... There's another way to skin the cat.
Here is what I did-
Begin a very friendly dialog with the people who will be doing the professional install. The dialog should include discussions on what you already have in place for them. In my case, I told them I already have a 28" dish aimed and working for 61.5 IRD. The cables are run through the walls and are accessable to the back of where the VOOM receiver will go. I told them I also have the OTA antenna that receives excellent quality signal on 3 other digital tuners. There will be a cable for that antenna run to the back to plug into the VOOM receiver. I told them the same for power and phone line, audio Fiber Optic, and DVI cable. They asked me what type of LNB I had on the Dish. I Told them it was the same one used for Dish Network and they were happy with that.
When the installer arrived, I greeted him with a smile and offered to first give him a tour of my current system beginning with my antenna location. He jumped out of the truck with compass in hand and ran to the street to check his direction. I waited, and allowed him to do his routine thing. When he began to shake his head, indicating he was going to have problems, I said, ready? Come over here to look at what is already in place. He was impressed with the install, inspected my grounding and complimented me on that. Inside, he saw everything was in place. I suggested he begin with the receiver and he did. 45 minutes later he was out and gone.
If you can't bypass the install process and want to be sure the wires are run the way you want, just make sure they are done in advance and most important, they work, are to code, and did I say, THEY ALL WORK!
In my case the installer had problems with VOOM and OTA not working. Since we had developed a friendly relationship from the start, he accepted my suggestion to prove the antenna feed worked and that he should try reseating the 8VSB module. He did that and bingo, the OTA worked. Then he called his boss and began bragging that my sat signal was 94. Seems it was the strongest signal he has seen. (Since the VOOM install I have tweaked the dish to get consistent 98 on the VOOM receiver.)
Maybe these suggestions can help you get the install done yourself without disrupting their company policy of "professional" install.