EMC CX4 & Hitachi Disks Multipathing

Hi,

We have Hitachi DF 700M disk storage and using it with HDLM for both windows 2003 and red hat. But we bought EMC CX4-120 but HDLM can't manage it. It shows LUn as 4 different disks. We are told that we have to use PowerPath but emc guys don't know what will happen if we install both PP and HDLM. So we don't know what to do.

in addition to that, we install PP to a server which HDLM is not available, PP didn't see the Hitachi disk storage too.

What is the best practice for multipathing for a situation like this? And where can we find answer? Thank you in advance.