Password encryption using vb3 md5.js

[*****Sniper]

I have successfully imported all forums and moderators from my old forum to vb3.
right now tho the moderators have an empty password field. reason being: not sure how to encrypt the password for vbulletin to understand!

so, in my password.php script I get the userid and password from my old database, store them in an array, and then what?

Is it possible to call the vbulletin_md5.js from a .php script and use it?
how do i use it? is it simply
$result = md5hash($myPassword[], $resultPassword)
[in the md5.js file is says "usage: md5hash(input, ouput)]
but then what about the 'salt' I have no idea how to go about doing this!
please help!