NET.EXE and the SHELL command.

Hi,

I have a problem hopefully someone could help with.

When I run "NET USE Z: \\Server\Share"  from the commandline and then run
a 
PB 3.5  program under Windows XP like:

OPEN "Z:\Test.txt" FOR OUTPUT AS #1
PRINT #1,"Hello"
CLOSE #1

everything works as expected, but if I instead run the NET command, using 
the same syntax as above, from a SHELL statement like

SHELL "NET USE Z: \\Server\Share"
OPEN "Z:\Test.txt".......

the OPEN statement causes BASIC error 76.

When I use "Windows Explorer" to see if the drive has been mapped it 
hasn't.(If SHELLing)
Why cant't I map the network drive from a SHELL statement?

Thanks for your time!