Editing sharepoint documents through APM

I'm working on this now, I'm doing the exact same thing. The weird thing about SharePoint is the following factors matter: Operating System Browser and Trusted Site Version of Office Sometime settings in document library * Opening documents in the Browser * Version -> Require Check Out (I have seen different behavior if checked Yes) The other thing to look at is are the credentials getting back to SharePoint when you try to open the document. One issue is that when you open a document in Office it establishes a new connection back to SharePoint. This is why when people are not on their corp network or computer they are prompted for credentials again. Right now I'm trying out cookie based persistence. This all assume that you are using NTLM or Kerberos.