How do you use a bitmap to pan in Sharp DX Direct 2D?

I'm attempting to display dxf files using sharp DX. It's running too slow while panning so I'm trying to use a cached bitmap during this but I can't get the bitmap to show in the correct location on the render target. I've a link below for the class in question. I've tried handling the transforms in many different ways but it doesn't seem to affect it. What am I missing here?

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