Mick Hardy
I've removed this information from the getting started guide so I thought I'd post it here just in case.

Magix Vegas 14 and 15 are now supported so this workaround is no longer required.

To download and install Sony Vegas 13 build 453 or lower and DVD Architect follow the instructions on this site. You can install the trial editions.

Older trial versions of Vegas are available from one of the the Vegas FAQ's below.