You'd just have to convert it to the proper decimal value. It's a little further complicated because the "Motorola decimal" isn't exactly the same as the "Uniden decimal".
If your FD is on talkgroup 3BC for example, you convert that to decimal, which would be 956. (You can either convert that online or in a spreadsheet program like Excel, or in the Windows calculator in Programmer mode.) But you're not done yet. That value 956 is what Motorola radios would use to refer to that talkgroup, but Uniden uses a different range of numbers (long story but it's owed to a fairly old mode of trunking and how different activities on the talkgroup were received at that time). You need to multiply the value you got from the hex to decimal conversion by 16 to get the "Uniden decimal" value. So if you have a hex value of 3BC, the value you need to program into your scanner is 15296.
Hope that makes sense - if you want to post your talkgroups, feel free to do so and we can convert them for you.