Where are you editing the values? In a window family or in the energy analysis settings? In a family the materials used define the thermal properties. You have to edit the material to produce the correct values. In the energy analysis dialog you are just choosing from a list of named glazing, you can ignore the names and focus on finding some close values instead.
There are two approaches to running the analysis, building as a volume with general construction characteristics (30,000 foot view, by adjusting/using energy analysis settings) or based on the building components you model. For the latter to work it takes more effort. You have to be careful to define/verify all the materials that are being used are reporting values you expect to require/achieve.
My other older self here: http://forums.autodesk.com/t5/user/viewprofilepage/user-id/46056
