create filesystem on file

Hello,

iam pretty new to SCO, installed it yesterday in vm. Now, i'd like to create a filesystem on a file like you can do on lnx or bsd. But seems not possible for me to do so on SCO OpenServer 6.0.0.

Thats what i get:

bash-3.00# uname -a
SCO_SV scosysv 5 6.0.0 i386

bash-3.00# mkfs filefs2
UX:mkfs: INFO: default type (vxfs) used
UX:vxfs mkfs: ERROR: filefs2 is not a special device and X option not selected.
So, i haven't found the "X option" ...?

Somebody has an idea, how to do that under SCO OpenServer?
Thanx,