I don't know about resolution.

There are two methods of recoding that I can remember of.

Blue > Activate PIP in HDMI mode ( something along those lines) > Record

Create an entry in a bouquet file using text editor. Stop Enigma2 with "init 4" before transferring
#SERVICE 8192:0:1:0:0:0:0:0:0:0:
#DESCRIPTION HDMI Input