Extend raid array on rx4640

[Juan B.S.R.]

Hi.
I have an Integrity rx4640 Linux box installed with RHEL AS 2.1, SA6400 and 1 x 146GB disk.
I need to upgrade this machine to 2 x 146GB disk and extend Raid 1 array without loss data and I don´t know how.
I think that the only way is make it with ACU but Support Pack is not available for RHEL AS 2.1 version.
In addition I have look for options in ORCA but only I can create, view or delete array.
There are any idea.
Thanks a lot.