Amit,
We don't import the avatar into AUP at all. It sounds like AUP has an option to show the K2 avatar?
Either way, since you're using Kunena to try to use the AUP avatar, that won't work.. since we don't import into that. We do have a profile plugin for importing the user's avatar into Kunena though. Does AUP have an option to use the Kunena avatar? Maybe you should switch from using the K2 profile plugin to the Kunena plugin and import the avatar into Kunena. Then, have AUP pull from Kunena. Kunena can then just use it's own avatar.
Hope that makes sense. You can always leave the K2 and Kunena profile plugins enabled, but then users may have to manage 2 separate areas for their avatars..
Alex