GuiXT Viewer allows us to introduce html files into SAP screens. All the normal html interactive possibilites are retained. In addition, it is possible to enter values into SAP entry fields, or to activate SAP functions.
You will need about an hour for the viewer tutorial. You will then be familiar with the two viewer commands view and viewHelp and you will know how to communicate with R/3 via hyperlinks and variables.
Details can be found in the documentation.