Ok, I guess it's not that hard to tweak, but it's neither essential for now, so I'll just park it. Thanks for taking the time on this Holch!

Just for info if anyone is still wondering what the "-1" lastpage is it's because the participant did "previous" on the welcome page.
We have "terms and conditions" that need to be accepted before the welcome page and if a participant accepts these conditions then he gets to page "0" (welcome page). If he uses "previous" on his browser after getting to page "0" he goes back to lastpage = -1.