a filesystem in a file

[Paul Branston <paul_(_dot_)_branston_(_at_)_freeserve_(_dot_)_com>]

In linux I can create a file then make a file-system in it, 
mount it and put files in it then write the file to a CD.
It would appear I can do the same with a svnc device but
I can't sort out how to make the filesystem in it. 

dd if=/dev/zero of=bigfile bs=1024k count=650

If I use newfs it complains that it hasn't been labelled.

Has anyone done this ? Could you tell me the secret please ?


thanks,

Paul