Why is it that the Karaoke and DDR series on Xbox don't work with the 360?

The online modes on the DDR Ultramix series were much better then Universe - and people would defintely play these games more if they did work.

I still play them on my original xbox.. 

Good question! I, too, have wondered that. Any info from Konami on this topic would be welcome!

Konami doesn't have control over what gets backwards compatibility. Microsoft decides which games are worth BC. Ask them about it.

I believe that, like MdXMaxX mentioned, this is more on Microsoft's shoulders than Konami's.

Here is Microsoft's Backwards Compatibility FAQ for your reference.  There is an email address in the FAQ you can contact to give feedback.

Maybe if a hundred or so DDR players e-mail Microsoft at once it will influence them to make the Ultramixes backwards compatible.  It's just a thought...

I have emailed them 3 times over the last 2 years about this..

everyone, please send emails to backcomp@microsoft.com! : ) 

ha, 360 so *** about making certain games playable. playing ps1 games on ps2 wasnt like this