shell -/bin/csh works, shell -/bin/ksh does not. HELP?

[screen-users]

Hi Folks,

I'm using HP-UX 11i, and the latest release of screen from the HP-UX
porting archive.

When I start screen with the screenrc file containing:
    shell -/bin/ksh
it does not start a ksh login shell.

HOWEVER
    shell -ksh
DOES start a login shell.  But my users are unhappy.  They want a shell
with a full path.

In addition,
    shell -/bin/csh
also DOES start a login shell.

The binaries all work the same:

-> which ksh
/usr/bin/ksh

-> ll /bin/ksh /usr/bin/ksh
-r-xr-xr-x   2 bin        bin         151552 Nov 14  2000 /bin/ksh
-r-xr-xr-x   2 bin        bin         151552 Nov 14  2000 /usr/bin/ksh

-> sum /bin/ksh /usr/bin/ksh
46868 296 /bin/ksh
46868 296 /usr/bin/ksh

-> ll /bin/csh /usr/bin/csh
-r-xr-xr-x   1 bin        bin         151552 Sep 10  2001 /bin/csh
-r-xr-xr-x   1 bin        bin         151552 Sep 10  2001 /usr/bin/csh

-> sum /bin/csh /usr/bin/csh
11072 296 /bin/csh
11072 296 /usr/bin/csh


Any ideas on how to get ksh with the full path to appear in $SHELL?

Thanks,
Judd Maltin