Maintain Login to WHMCS when browsing WordPress

my WordPress 3.0.4 install is the site root and i have WHMCS installed in /hosting

and just so its clear i am not trying to bridge wordpress to whmcs just maintain the login session to whmcs.

here is what happens.

if a user logs into WHMCS and browses to any page not in /hosting then returns to /hosting they must log back in.

is there anyway to maintain the login session? there seems to be something in WordPress causing it to clear the session.

some things i have tested.

if i go to another website and come back to /hosting i am still logged in.

if i login to /hosting
1. open another tab
2. go to my site root in the new tab
3. return to the first tab and navigate to another page in /hosting i am logged out

Regards

Sean