Migration data from 1.6 to 1.7 didn't migrate visitors data, all statistic are corrupted

[ballashop]

Hi,

first... this migration was done on a test site.
So the operating site is still in version 1.6.

Unfortunately we didn't update to the 1.7 by the native upgrade module because we had a lot of problem and errors after first test. So we thought to use a module to migrate; the developer was very helpful in helping us, but...the "visitor data" since we put the site online have not been migrated so all the statistics are corrupted!
Do you know another way to only migrate the visitor data?

For data statistic I mean all the data connect to the visitor data.
Thanks for any suggestion.
E.