It would be great if you added Volkov Commander to the file managers.
Use the alpha version. It's been alpha for over a year now, and everybody I know uses it for free. You could even add some of the Plugins.

http://www.egner-online.de/vc/en/downloads.shtml

I look at the FDUBCD.IMG and found in directory level1 file VC.CAB!

The Volkov commander is there!

But better will be to move it to dosapps...

Yes, Volkov Commander 4.99.08 alpha (official freeware) is included in UBCD v3.4, inside FDUBCD menu choice [F6-F1] FreeDOS Boot Disk V3.35:
Q:\>VC
(although Help seems missing)

But it would be better if it were easier to find, not so hidden! Until it is provided in a separate form, the best thing would be to add a menu entry at [F3>>] File Tools with the other file managers, that just points to the same batch files as [F6-F1] FreeDOS Boot Disk V3.35 but is labelled plain "Volkov Commander 4.99.08".

(It seems like you can choose almost any of the File Tools and get VC automatically as part of the standard application launch process.)

I should have no problem adding this in the next release.