If the function is on the original remote, you can teach it to the 3100. The square key in the upper right hand corner below the power key can be used to learn the DVD input, and if the letters DVD don't show up you can select it. Pick any other square key, or a label button so you can relabel it to read SAT, and you are set.

You can also learn any functions you need that are not there from any of your other remotes.

In case you haven't seen all this stuff, I will post it here for your information.

RM-AV3000/3100 NEWCOMERS PACKAGE-WELCOME-CHECK THESE OUT (IF YOU HAVEN'T ALREADY DONE SO) AND SAVE YOURSELF SOME PROBLEMS

SYSTEM CONTROL KEYS: Everything you need to know about them

HOW TO LABEL, CHANGE OR HIDE BUTTONS

CHANGING BATTERIES (May not be necessary on RM-AV3100, but why take a chance when it's only 20 seconds?)

AND IF YOU HAVE A SONY RECEIVER:
HOW TO CHANGE YOUR RECEIVER AND REMOTE TO AV1 (or AV2) COMMAND MODE

AND HERE IS SOME MORE INFO IN CASE THE MANUAL GETS TOO CONFUSING

REMOTE CENTRAL RM-AV3000/RM-AV3100 FORUM REVIEW (INCLUDING THE QUICK PROGRAMMING GUIDE)

Also, check out the TIPS AND TRICKS section.