Hi, I'm new with elgg and I'm having just the same problem.
Did you finally solve this issue? Could you explain how did you?
awww heckz - dis a an olddd post - me not remember.. ;-) i reckon since then we have some plugins to do what Niels had wanted, I posted @another Topic past few days - look for Afioni & SiBaz's plugins for 'Remore Login'.. maybe outdated @ v.1.7 - but hey who cares ? can always update the code here & there abit and make it work ;P