[imp] Session ID adding to every link on my site!

[Nicolas [HiTech Planet]]

Hi,
I integrated IMP into my main page, at http://email.hitechplanet.com, and it
works all fine, except for the links, that are not related to IMP. The
system adds the Horde session ID at the end of the urls as a query string...
Look at the links on the left side of the site (like 'inscription',
'partenaires', and such).
This is probably due to the fact I integrated the custom login page to the
main page of the site, but as it is required for the login to work, how
could I prevent it ?
Thanks in advance for your help.