How to allow a non http(s) url in a rich text field

Dear community, I would like to use some links in itegrity. I created some doors/svn links (they are working well e.g. in a browser) Integrity says: "The hyperlink "svn:file:\\\....." is not supported. Please check with your administrator to see which hyperlink protocols are allowed. In the documentation stays: "mksis.url.protocol=" can only http or https what if I would like to use other protocols many thanks for your answer in advance