Avamar do support ESX 3.x image backup

in the compatibility guide and admin guide, it says Avamar only support vSphere 4 image backup. but:

1) when i do POC with AVE, it works with ESX 3.5.x

2) more important, the competitians all support ESX 3.5.x and ESX 3.0.2.

it seems avamar has no reason to do this, because it can do it.

and all backup software implement the vStorage API  DP, there will be no big difference between them, the key is VMware API.