I have the Motorola U-Verse ATT box and my DVR is full.

I have a Toshiba DVD recorder, which I want to use to record to DVDs. Right now the DVR box is connected to my TV (a HD tv) with the Colorstream Red/Green/Blue cables, and the DVD player is connected with HDMI. Can I record to the DVDs in HDMI? From what I"ve been reading you have to record with one of the RCA red/yellow/white cables, is it possible to record to a DVD in 720p? If not will it be upconverted when I play it?