Seems this software have a public API
http://blogs.ptc.com/2015/03/23/ptc-mat ... 1-api-sdk/ might be possible create something specific for it. All in depends about what you have in mind. Seems there's and add-in
http://www.ptc.com/engineering-math-sof ... soft-excel but take in mind is an application ( excel ) what is connecting to mathcad. If you want to add a new icon into matchcad ( I do not know if it's what your thinking about ) should ask with this company if it has some plugin system or similar for extending matchcad features.
Hope I have help you in some way ?