When we looked into PTC's offering they had a viewer that would allow the viewing of hotspotted documents and integration with an external shopping cart. Note that at the time this was a plugin and thus did not support iOS.
You're overall endeavor is actually a number of pieces. I know there is a company out of Italy that does such a thing but it is basically image mapping and would not work directly with IsoDraw for instance.
For our purposes we ended up doing a custom solution. Our documents are maintained in IsoDraw and we utilize a macro to apply appropriate metadata. We display utilizing svg for modern browser (swf for older versions of IE). Works very well and has been in place for close to ten years. We actually started with Micrografix Author for editing and migrated to IsoDraw about seven years ago.
If the link above does not work, go to the following link and the diagram is linked from the lower left.