Cisco 5428-2 ISCSI Brocade switches SAN

Hi ,

anyone out there who has configured an 5428-2 iscsi router
connected to IBM s16 FC switches (Brocade OEM)?
The FC switches are connected to an IBM ESS F20 storage.
Without the Cisco's the SAN is performing well , running
in "brocade" mode and giving no problems. By connecting
the cisco's i have to put fc interopmode on and to switch
from port zoning to wwn zoning. Starting up the san switches after
these changes is ok , switches are healthy and the cisco's are learning
the configs from the brocades. Because of the changing from port to wwn
zoning i had to put in all the wwn numbers to the correct zones by hand.

The starting up the servers brings now the problems , some servers
ok , others are not seeing there disks , Sun servers are seeing there
disks but very slow in access , having i/o timeouts , our ESX server
with 4 FC cards only connects by 2 or 3 cards (several boots initiated).
A whole mess.... returning to the old config , port zoning no cisco ,
and all is running perfectly again.

I spent now two saturdays figuring out why this happens , is
it a non compatibility between brocade and cisco , or is it the
interopmode of the SAN.

Are there any parameters needed in the configs of the FC cards in the
servers or some special configs to make for the brocades or the cisco's?

Thanks in advance

Marcel Hoffmann