I understand that you are having some issues in order to connect the Direct TV-H25 to your Slingbox AV, due to the lack of outputs on the Direct TV boxes.
In this case, there are two options. First, get a replacement for the Direct TV and get a supported model. You can use the following link in order to use the included widget.
Your second option is to upgrade to the Slingbox SOLO or the Slingbox PRO HD. The following link will allow you to take advantage of the Slingbox Upgrade Program.
Finally, the following link will allow you to get all the information about the Slingbox SOLO and Slingbox PRO HD.