How do I attach a ledger to a stucco wall?

I am looking to build a patio cover this summer and I would like to attach it directly to the house vs. a free standing structure. The wall is a 1 part foam core application, run of the mill for tract homes. I am pretty sure there is an 3-1/2" x 13-7/8" LVL or Paralam beam running the length of the house that I could easily attach to using lag screws. The only thing I am really uncertain of is how to flash and waterproof the area I will be modifying. If anyone can help or direct me to a website that will explain the steps I would appreciate it.