The filter property needs to see an array, and in kixtart, one way to specify arrays is by saying this:

$array = 1,2,3,4,5

So, you say this:

$domain.filter = "service","user"

or to just specify one class, say this

$domain.filter = "computer",""

we just provide an extra null "" element in the array to get kixtart to pass the property as an array. ADSI sees the second, null elementbut just ignores it.

Did that answer your question ?

-Shawn