Ghost.exe is fully navigable via keyboard - so you should be able to get by without a mouse.
The mouse drivers were omitted from CD boot packages as the drivers attempt to write to a file when they load - and CDs are read-only. However, it seems that some people have had success adding mouse drivers to their CD boot packages for GSS 1.1 (I doubtful that their solution would work for older versions of GSS and Ghost Enterprise)
See this thread: http://forums.veritas.com/discussions/thread.jspa?threadID=62721&tstart=15