Clariion CX4 Trespass Question

Hello-

Hoping someone can assist with a situation we have, or at least help me understand why it is occuring.  We are in the middle of migrating a variety of windows, esx, aix, linux systems from an IBM SAN to a Clariion CX4-240, flare 29 sp3.  Because of this temporary situation we have the CX4 spa1 and spb0 going into the two switches that are currently connecting our systems to the shark and CX4 spa0 and spb1 going into two new mds 9134 switches.  With this setup our hosts are able to see data on th shark, via the old switches and can see the luns on the clariion through the new switches.  We are in the middle of migrating the data from the shark to the clariion.  Each time we finish with a system we pull its fiber cables from the old switch and cable it directly into the new switch.

The problem with this is we are using unlicensed powerpath on the windows hosts so we are only leveraging one hba.  When the project is done and all four sp connections are in the switch this won't be an issue if we have a trespass because the hba will have a connection from the switch into spa and spb.  But, right now if a trespass occurs the LUN is dropping, since basic pp will not trespass at the hba level and the switch only has a path to either spa or spb, but not both.  To deal with this short term issue we are being very carefull to not trespass any LUNs.  Now the issue.....

At randoms times we will get calls from our database team stating a drive has dropped and when we look at the window system we can see a trespass was initiated by the client, but since it can't get to the other sp, the trespass fails and the drive drops until we manually trespass it over.  This happened again today when we added an ISL connection into the MDS switch to add one of the blade systems we need to migrate into the fabric.  We made sure the domain ID's were higher on the switch we added so it wouldn't cause switch conflicts.  It also happened a few weeks ago when we added a few hosts into the Navisphere manager.  All we did was register the hosts and add them to some storage groups and once again some LUNs dropped.

Native MPIO on the linux systems seems to be dealing with this issue okay and LUNs seem to be trespassing fine, just 2003 windows boxes right now.

Does anyone know why these types of activities, adding an isl connection to a switch and adding hosts to the clariion, would cause this issue?

ps.  I would add the licensed version of powerpath if my customers would pay for it....I guess once all sp paths are set at the switch level I will be okay, but it is frustrating and emc can't really explain it, or I at least don't get what they are saying.

thank you