Silverlight4 & Which .Net Framework to use????

[AngelGonzalez]

Questions to you silverlight experts.  What .Net framework should I use to develop Silverlight4 app. in?

I created  a simple helloworld SL4 app and deployed it to a server and it blew up due to the fact my app. was targeting the .Net 4.0 and the server did not have it. I changed the framework to 3.5SP1 (which is on the server and it worked).  To take advantage of the new SL4 functionality and with the upcoming ESRI SL 2.0 version do I need the .Net 4.0 Framework or can everything be done in 3.5SP1 Framework?

Note, I am a beginner in SL  and just installed VS2010 on a test machine.

Thanks

Angel

[dotMorten_esri]

Your solution is to run your WCF website in a separate app-pool from ArcGIS Server. Only this apppool should run on .NET 4. Leave the app-pool that ArcGIS Server runs in at .NET 3.5

[PLadd]

Thanks Morton.  That's perfect.  Just the advice I needed to figure this one out.  It works great now. 

For those who are novices with IIS like I am, here's a link to set up an application pool: http://www.developer.com/net/asp/article.php/2245511/IIS-and-ASPNET-The-Application-Pool.htm

Then go to the properties for your web app in IIS and repoint your application pool on bottom of Directory tab.