Can't get into DFU mode from Activation screen?

[moviecouple]

My iPhone 2G, when I sync it, comes to the Activating screen because I got the 3G iPhone too.

I have been trying for 2 days now and cannot seem to get into DFU mode. Is it even possible from and de-activating 2G iPhone?

 

[RFR79]

See if this helps: http://www.youtube.com/watch?v=M2foiTBSn3k

 

[AustinSTI]

Similar problems with one of mine...the video doesn't work. The apple logo always comes up..