Manually importing users from 1.1 with phpmyadmin

[al_foto]

I need some help by migrating users from an old Virtuemart 1.1 + Prestashop shop to 2.5, the shop is no longer available but I have the tables.
I have got to create a csv file with all data and the field names match the ones in the 2.5 table structure but I'm not sure how to add them. I have tried using CSVI but the virtuemart_userinfos table was not filled and this was actually the one I selected in CSVI.

Also I need to know where to save the VAT number of the old users, can't find any field for it, should I create it first as extra field ? But in this case can I handle later VAT exemptions if I install the VAT Id Checker ?

Any help will be appreciated 

[PRO]

I would install the old versions on a development domain.

THEN: replace the tables whith the new 1.

THEN: migrate, then export that db, and into the new site.

OR:

ALSO: the NEW vmart migrator uses the old DB prefix to recognize the info to migrate.

old vmart is   _vm   new vmart is _virtuemart

BUT!!   I hope you have the JOOMLA user data right?  Thats where the passwords etc. are

[al_foto]

Installing old Virtuemart is not an option because as I said they are also records from Prestashop.

I think I have got it using CSVI but still no clue about what do with the VAT number.