Can A 6300+ Using Simul-Task Be Upgraded To MS-DOS 3.3?

[M.LISS]

My AT&T PC-6300 PLUS 20MB C Drive is currently partitioned
"by the book" for Simul-Task.  Because of my desire
(pertaining the computer) to have a 3.5 inch drive though, I
purchased MS-DOS 3.30.  Lo and behold, Simul-Task wouldn't
let me install it.  I managed to "fdisk" to the other
partition and load it on the small MS-DOS section.  But it
seems silly to have THREE OSs on the machine (UNIX, MS-DOS
3.1 and MS-DOS 3.3), "fdisk"ing all the time.  Of course, I
could make it a straight 3.3 unit and take advantage of the
2K speed versus 3.1's 8K, but then why have a PLUS?  My hope
is to get advice as to how I could make the machine play
UNIX and MS-DOS 3.3 under Simul-Task.  I would even get the
Simul-Task used on the 6386 WGS since it supports MS-DOS
3.3, but am told that it can't be used on the PLUS.  And
since the PLUS has been discontinued, there are no plans to
upgrade Simul-Task for it.  Any suggestions?

Marv