Some more hickups using J1.7.3/VM2 revision 4911:
After applying the b version, I ended up with empty _virtuemart_vendors_de_de and _virtuemart_vendors_en_gb tables (Shop is set to multilingual).
The information in the _virtuemart_vendors table appears to be somewhat truncated. Looking at the database table, the vendor name is filled with my street address, store name field is empty.
Problem now seems to be that I can't store my vendor information from VM admin in the new en-GB and de-DE tables. Vendor Shop Name and Vendor Additional Informations aren't stored. Shop Company Name does get stored.
After clicking 'Install tables or if necessary update them', VMDebug still tells me this:
vmError: TableCustoms The given Title is empty. This field is obligatory, please enter your data and store again.
Does that mean it I have a missing title in the _virtuemart_customs table?
Update:@Milbo - After re-entering the somehow corrupted Vendor Information manually into the database tables again, I finally got my calculation rules back.
Update 2:Bad luck again - the calculation rules are ommitted in the frontend views. Only currency exchange rate is applied to the cost price. In the backend the calculation rules seem to work ok.