Xbap Application behavior change with or without "www"

We are writing and running a xbap application. We use URL parameters to change the application's behaviour when the user logs in. To do that we use System.Deployment.Application.ApplicationDeployment.CurrentDeployment.ActivationUri.Query to get the URL parameters in the application.

Sometimes (and this is hard to reproduce), we get different behaviours 开发者_如何学Godepending on whether or not we use www in the URL (i.e. http://myapp.com/app/App.xbap?para1=para vs. http://www.myapp.com/app/App.xbap?para1=para). We have checked with our hosting provider and they recommend using links without www, which we've been doing ever since. Regardless, in some cases, the first link will work just fine and some cases it'll work as if there were no URL parameters (i.e. if I went to http://myapp.com/app/App.xbap). We have noticed that in these cases, adding www (going to http://www.myapp.com/app/App.xbap?para1=para) to the URL will result in the desired behaviour. We have also noticed that in these cases, ClickOnce will download/update some of the xbap application even though no updates were published.

Any help on resolving this issue would be much appreciated. What can we change to guaranty that our application will always work regardless of www vs. no www?

thx