Thanks. I looked at their drawing (Transmog-Shield-v01.pdf), and rather than ordering one I decided to make the mod myself.
I cut the legs off D11, D12, D13 on my header to the USB Host Shield and jumpered in from the ISP header SCK (ISP pin 3 to D13), MOSI (ISP pin 4 to D11), MISO (ISP pin 5 to D12).
It works perfectly now. I appreciate you pointing me to this.