Ah, Google tells me that this is actually a combo TV/VCR/DVD unit? In that case, the unit requires 3 different device codes. So here's some things to try.

Use your URC-4063 with setup code VCR 000. Make sure you're on VCR rather than TV. Check to see if any buttons work. If you have a silver Comcast, you can try that too, with Video 0000 or 20000 for the red button version.

You can also try the following EFCs.

To simply test one of these EFCs, press VCR (after assigning the setup code VCR 000)
For each code, press Setup and then enter in the 3 digit EFC. If using the Comcast remote, enter 5 digits--00 followed by the EFC.
device number 40             44             41

0	081	073	097
1	242	234	002
2	209	201	225
3	207	199	223
4	211	203	227
5	204	196	220
6	208	200	224
7	206	198	222
8	210	202	226
9	077	069	093
channel up	109	101	125
channel down	045	037	061
power	205	197	221
menu	112	104	128
display/info	174	166	190
exit	050	042	066
up arrow	047	039	063
down arrow	236	228	252
left arrow	044	036	060
right arrow	172	164	188
tv/vcr	173	165	189
play	047	039	063
pause	051	043	067
rewind	044	036	060
fast fwd	172	164	188
stop	236	228	252
record	239	231	255
eject	016	008	032
search mode	178	170	194
slow	048	040	064
speed	019	011	035
auto repeat	237	229	253

To assign one of these codes to a key, press VCR
1) Press and hold Setup until 2 blinks
2) Enter 994
3) Press Setup briefly
4) Enter the EFC either 3 digits (or 00+ the 3 digits if Comcast)
5) press the button you want this function assigned to.
shoud get 2 blinks