You will eventually get it. The 5vr backs best in a slow arc. Mentally picture a length of hose laid out on the ground in a sweeping curve. That is the 5vr path. With a TT you can tighten up that arc and recover fairly easy because it happens quickly. With the 5vr you can make it turn tight but when you do you start moving the front of the trailer. So what happens is you get the rear wheels on the path that you want them, and start cutting back to continue straight, well it takes so long to get back "under" the trailer that your trailer wheels are now past the line you thought you were going to follow. A quick pull front will straighten things out.
The angle your towing vehicle is in in your signature is about perfect for turning your 5vr.