I solved my problem so if anyone is trying to make and host silverlight application first must read carefully
this.
In short - silverlight app can make calls to resources such as databases through web services. I successeded to host only 'WebService' (asmx file) with cassini, not 'Silverlight Enabled Wcf Service' (svc file) nor 'Ajax Enabled Wcf Service'.
Here is the process step by step:
1 Create Silverlight project for the app itself (the interface).
2 Create another Silverlight project for the WebServices (it might be differet type of project but this works fine).
3 Add the 'clientaccesspolicy.xml' to the root where the web services are (the content of this file is in the above link).
4 Host the web services project with cassini and give him static port. Test the service, just type
http://yourStaticIP:yourStaticPort/yourWebService.asmx 5 Host the Silverlight app those with the interface.
6 Add the newly created service to the app's coresponding web site. Use your path with the static port when searching for the service (
http://yourStaticIP:yourStaticPort/yourWebService.asmx).
Hope that helps. Take care!