This is perfect and cheap.
There is also a Cleon II with more features but the Cleon I does the job fine.
You plug the C6 cable into the Promote and the Promote into the camera remote connection. Just so happens the Canon 450D, 500D XTi, XSi, T1i Rebel etc have the same 2.5mm mini plug as the Promote.
So the wireless will not work with the promote unless the wireless uses and c8 cable?
Here is a posting from another hdr blog. I am not sure if one of these will work:
try to get your hands on a remote cable with a 2.5mm jack, like for canon rebel etc - it will fit the promotes remote port - or get one of these for wireless operation -
both available here - "C6" is the 2.5mm cable - http://stores.shop.ebay.com/Hong-Kong-Supplies__W0QQ_armrsZ1