I am running the FH05 Radio, with the euroskank nightly, Franco kernel and my apns changes (which I forgot to copy over yesterday and did not get an ehrpd until I did that and rebooted. I was able to get 4g/ehrpd yesterday without a problem using that config.
The other things that I did I do not remember specifically, but they all involved playing around with things in the debug/data menus on the phone (a great utility for easy access to them is here: http://forum.xda-developers.com/showthread.php?t=1774503) I only remember playing around with settings related to either eHRPD or LTE in there...
Hope that can help you out...
On a side note, there there is a neat section in "Data->BSR->View LTE_available file" which seems to be how sprint reduces the battery drain from scanning for LTE signals. By defailt it appears to scan for LTE rather infrequently (Looking at the settings I would guess 30 seconds), however once it finds that it can get 4G in an area it stores it in the table with the relevant CDMA SID/NID/BSID so that next time the phone is connected to that tower it knows it can scan sooner and get 4G (However I believe that it does not mean that the tower listed has 4G just that it is getting 4G from some tower while it was connected - for example you could have Tower A 100 feet from you but be getting 4G from Tower B 1 mile away and it stores the info from Tower A).
So whenever you go to a new cell with 4G it will take longer to find the signal, subsequent connections will be faster. My table has 71 sites entered for where it has detected 4G (I am pretty sure this is created via discovery by the phone and not sent by Sprint) it had 69 before I drove up to Andover yesterday so I obviously picked up two new sites where 4G can be recieved.
Geoff