Custom Partition Size on RHEV-H 3.0

How to set custom partition size of various partition on RHEV-H 3.0 (Evaluation version)

Documentation mentions to append "storage_vol ..." parameter in 

boot menu kernel parameter but it dosen;t.

Specifically how to increase the config default partition size from 5MB to some 1024MB

i tried 

storage_vol=:4000:1024:2048:-1 but it seems to work.

TIA