Migrating all product images

[ST]

I migrated successfully from Joomla 1.5.25 / VirtueMart 1.1 to Joomla 2.5 / VirtueMart 2.0 about 2.5 weeks ago. However, I just noticed that now only 1 product image per product is available.

Is there currently a method to transfer all images?

If not, can anyone give some hints/suggestions where to start if I want to achieve this for a large number of products?
So: how are the images and database-entries for products linked in VM1.1 and how are they linked in VM2?

Thanks in advance!