RHEL5 and iscsi vs local partition mounting

[Scott R. Ehrlich]

A colleague has a white box (COTS) intel server directly connected to a 
large disk storage RAID system (build by some random company).   The 
server and storage are a single chassis.

The RAID consists of some Linux partitions and some NTFS partitions 
created by an iscsi connection from a Windows 2003 server.

Now, the admin of the system wants to have simultaneous access to either 
file system (ext3 and ntfs), regardless of iscsi or locally mounting it. 
The iscsi Linux drivers were obtained and installed directly from the open 
iscsi web site.

In tests, locally mounting an ntfs volume under RHEL5 prevented a Windows 
2003 server with iscsi from mounting the same volume, though the W2K3 
server was able to log in via iscsi.  In the other direction, with the 
W2K3 server logged in and ntfs filesystem mounted, local mounting of the 
ntfs volume under RHEL5 failed.

Is there any practical reason why both locally mounted and iscsi mounting 
cannot work simultaneously?    Is it part of the iscsi protocol that data 
protection prevents simultaneous access?   Or, is there a setting in the 
iscsi config file on the RHEL5 hosting server that can permit simultaneous 
access?

Thanks for any insight.

Scott