Multipath for Linux

Greetings,
We are implementing a cluster solution with Linux RH Enterprise Edition 4 in a Proliant DL380 G4 and a MSA 500 Storage, with Service Guard for Linux and Multipath Software and everything is working well except the multipath funcionality, which should be able to view the disks at MSA trough both controllers, 0 and 1. It is true untill the machine reboots, when only one controller goes up, which means a Single Point of Failure if the server reboots sometime. We already looked at web and even contacted HP, which doesn't know what is going. Someone have some clue?

Thanks,