This threw me for a loop today. You can't call a PowerShell function with commas "," or parentheses "()" and have it believe it goes to both parameters. Try running the following and see what your output is on every line call to "foo."
function foo([string]$a, [string]$b)
{
Write-Host "a:", $a, " b:", $b
}
foo("A", "B")
foo "A", "B"
foo "A" "B"
foo("A", "B") "C"
rm function:/foo
You may find you get different results than you may first expect. I did.
Reference: http://weblogs.asp.net/soever/archive/2006/11/29/powershell-calling-a-function-with-parameters.aspx