Joomla woes

[eluser]Dam1an[/eluser]
After a little bit of digging around (only a minute or two thanks to eclipse being abe to jump around and make better sense of the structure then me)
You want the onAuthencate function found in /plugins/authentication/joompla.php (line 55)

That calls an encryption function call getCryptedPassword which is in /libraries/joomla.user/helper.php (line 106)

If you just include that function and call it, you should be OK

Edit: that was Joomla 1.5.11, so line numbers might be slightly differant if you don't have the latest stable version