Which web clients does this other company use? Tokens will work with WMS in a web client, but ArcMap as a client won't request a token for WMS. For instance, they can append a token to the end of a web request and access a secured resource if your customer is working with web apps instead of a thick client.
Yes we tried token with a web client and it worked but other companies want to consume the service in ArcMap,Qgis etc.. So we need a common way to sharing services.