Passing JavaScript Array Of Long To Code Behind?

I have returned object from signature device and when i make quick watch on it, it told me that its an array of long and when i pass it to web method in my code behind (vb.net) it gives me nothing. note: i'm using an activeX to capture the signature from the device.

this is javascript code :

function OnSave() {
var sign = document.FORM1.SigPlus1.SignatureString;
PageMethods.Save(sign);
}

this is my webmethod:

<WebMethod()> _
Public Shared Function Save(ByVal obj As Object) As String
Dim obj1 As New PFSIGNATURELib.SigniShellSignature

[code]....