Need 6.5 Gallon Boil For 5 Gallons

Okay... I do full boils in my keggle.  What I consider a moderate rolling boil in my keggle typically boils off 1.5 gallons per hour.  I know that one gallon per hour is typical, but that is what I'm getting, so I do a 6.5 Gallon boil.

How do I adjust BeerSmith to accommodate the extra water without lower my overall OG.  Obviously, I need to add more grains/sugars to make up for this additional needed water, but how do I do this accurately with BeerSmith?

Thanks!

In your Equipment Profile.  Start on the right side with what you want to finish with, and work up that right-side column and then to the bottom-left, filling in what results you get on your system.  It will add in the other losses that you're not, such as shrinkage to cooling, etc. 

there's a couple good posts here that may be pinned to the top of the section; I don't have them handy, but others refer to them often.

Thanks for the reply MaltLicker!

I'll give the posts a look and give it a shot.