With changed File-Mappings you can only control how the ide treats the file, it wont download the content of the file to the target tough.
I think the simplest approach, and probably the best one too, is to store the content of the file as string literal as part of the application. So it wont be a separate file anymore, but everything is straight forward, no custom build steps.
If you really want to put the content of a file into the application, then the only way I see is to create an srecord out of the html page and then include the srecord in the prm.
The linker supports to include srecords, and the conversion from a binary file to an srecord can be done with the burner in a batch burner file.
I'm not going into too many details, as I think the simple code it as string literal approach is still the best one :smileyhappy:.
Daniel
BTW: I think processor expert has a bean for such purpose, but processor expert is not an option with the HC05. I'm sure there are many tools on the web too to encode a file into a C source file.