Hello Nikia,
Yes, I did figure this one out. In the scheme settings dialogue box for your window schedule, go to "add fields". Under general, select one of the custom text options, then add it to your schedule. You then can change the name from custom text to SHGC in the actual schedule. I tried to attach a photo, but I do not see an option to do so. If you need more help, give me your email and I can send the photo to you.
I have the same issue, but I am unable to check Rich M.'s answer. Stephen did you solve this issue yet?