I have a WMS layer served with ArcGIS for Server 10.3.1. I would like to embed this layer in an ArcGIS Online App and use a Pop-Up to show information about the points. As one of the fields contains URLs to Images as field values, I would also like these images to either be linked via "href=" or even better shown as a thumbnail miniature in the Pop-Up and when clicked upon opened in a separate browser tab.
I am having the following problem: I have a valid WMS layer which is displayed in ArcGIS Online without a problem. But in order to get the pop-up windows working I had to create a custom XSL Template. I can however see no way to define to ArcGIS Online that this is the only layer that needs the custom template. It only works when I rename the custom template to the standard wms GetFeatureInfo template. This means however, that every other wms GetFeatureInfo will not work with it. And all other WMS layers will have no Pop-Up windows.
Does anyone know how I can tell ArcGIS Online to use the custom template with the WMS Layer? Is there maybe another way? I cannot use WFS because ArcGIS for Server throws an error when I try to link an external GetCapabilities Document to the service definition, and I cannot use the rest interface as my rest services are not accessible over the internet.