Hi,
The conversion can be done by using very powerful tool which is part of Forest Pack Pro called "
Forest Tools". This allows you export your distributed geometry to instances. It can be found it under
Utilities panel -
More ... -
Forest Tools. You have a lot of possibilities what will happen with your instances after conversion to mesh (for example moving all instances to new layer is very useful).
All these Forest items (having the proxy object selected as
Custom Object) will be converted to instanced proxy objects -
VRayProxy /
CoronaProxy /
mr Proxy pointing to source files (not meshes).
Hope that helps.
Best regards,