I don't know if you're in touch, but as other Maemo's hacks, it is possible to edit hildon-welcome screen, in case you don't know ho to do it :

1- Copy (with the help of this tutorial) the video to /usr/share/hildon-welcome/media

2- Go to /etc/hildon-welcome.d/ and edit the default.conf file or create a similar one (the videos will play by the alphabetic order of the .conf files)

In case you don't want to do the Step 2, simply rename your video file into Hands-v32-h264.avi and overwrite the original one in Step 1 ;)

Some examples here and here.

Via : talk.maemo.org