Something is askew???
When you change from a Disc/Drum set up to a Disc/Disc set up you have to change the master cylinder cause a Disc Caliber uses more fluid than a drum cylinder. I am surprised that the manufacture told you that your current system would work. If everything brake wise, on the car worked normally before you changed over to the Disc set up and now it doesn't it sounds like you pedal is reaching full travel before you get enough fluid back to the brake to even bleed it correctly let alone build up pressure. I use a brake Pressure gauge when I start to have to issues that aren't easily fixed. I will test the output pressure from the MC through the proportioning / combination valve to confirm that area is good first SSBC sells a nice kit you can get for about $50-$60.
Checked out your ride looks great to bad you don't live close by we could bring it in the shop and fix you up. Don't have enough room to in here to go step by step to help you thou.
Maybe a call back to your manufacture tech depart would help or even another manufacture tech could help you I have found some tech guys are very knowledgeable and some well lets say I have wasted some mins on my cell phone at times too.