you say that even with Glideslope you cant get the Shuttle into that atmosphere. This is hard to believe, as I find Glideslope MFD makes it very easy to manage the descent. Make sure you are using the automatic steering. This will hold your AoA at 40 degrees and makes performing the S-turns much simpler as it allows you to change the bank, and when you stop pushing on the stick it will damped and hold the bank angle, all the while also holding the AoA. If needed, a little back pressure can be applied to further pitch the nose up, usefull in killing some velocity.
There are two key screens in Glideslope to use, one is the vertical situation screen which shows two lines, your velocity and your altitude, and then shows the path you have already crossed. The second screen is the one with tapes of various information, as well as markings for which each value is supposed to be to maintain the corridor. If you see your altitude is too high becauce the 40 degree AoA is creating too much lift, start an S-turn, of at least 60 degrees and hold it and the lift will go away, allowing descent.
