What are you trying to move? virtual pools? can you be more specific? I know that EMC offers something called “San Copy” that allows you to make copies of luns from arrays to arrays.
I’m pretty sure that HP has some level of either host-based or array-based synchronous or asynchronous replication software that would allow you to move LUNs or storage pools from one array to the other and then cut over the the affected hosts.
there is no such thing as an array migration without downtime unless you’re using something like IBM’s SVC or EMC’s GFV (Rainfinity) or Invista. Those appliances virtualize the storage systems behind them such that volume moves can be accomplished with full transparancy.
Alternatively, if these are VMWare VMFS volumes, you could use Storage VMotion to move from one array to the other. the Host would just need visibility to both storage systems.
hope that helps!