I don't know much about the Philli BEC info, but

I am also looking at converting RIR to Perm and I found this old link from one lawer here, from what I read, it looks like you can do that, You have to keep the old RIR and get another one use Perm then use the old RIR priority date to do the 140 and 485. Here is the link, you can check out yourself:http://immigration.wenxuecity.com/BBSView.php?SubID=fyy&MsgID=654