Strange url behavior

[asteconsulting]

Hello  ,
Whit Joomla 1.5.22 and VM 1.1.7 i have a strange bahavior.

I have two pages in joomla with two different menus but both have a link to virtuemart: my problem is that if I go to virtuemart from page 1 my url is www.mydomain.it/page1? and does not change if I go from the link on page 2, so if i'm going back i return at page 1 and not at page2 from where I entered.

In this case, how can I go back to my start page (page 2)?

I hope i was clear and sorry for my bad english.

Thank you all.