Hello, unfortunately there are no documents on how to do this process as it can take several forms. The unfortunate part is that both products have been End of Service Life and garnering aide from your local CSS/Global Solutions team may incur a cost.
The best methods to use for such old combination is to stand up HNAS 5000 series connected to VSP eX90 and object\file replicate from one system to another.
On copy is one our Technical Experts from the region, so he may be able to point you towards local teams for deeper assistance.
@Mandar Bhide