I couldn't have said it better! The key is that you'll need temporary support in order to suppor the load while you install the header. This is where the Engineer or Architect comes in. (If the Architect can't help you, ask for a reference for a Structural Engineer.) He/She will tell you the beam specifications you'll need and what you'll need to do to support the load. I can say this - The MOST common problem a DIYer does, or forgets to do, is build the 2 temporary support walls AROUND the beam. In other words, you'll want to lay the beam DIRECTLY under the ceiling area in which you want to install it. Then, you build one temp wall at one side of the beam, then the other temp wall on the OTHER side of the beam. When this part of the job is done, you have your 'original wall' AND the beam kinda 'inside', or between, the 2 temp walls. See what I mean? If you don't do this, good luck trying to 'slip' the new beam in between your temp wall(s) (even if the original wall is demolished!!! Usually, it can't be done. If you need to drill holes through your new beam, just ask the Architect/Engineer where and how to do it. Actually, talk to them about this when you meet w/them so they know if what you want is doable or can be worked-around.