yes, I think it should be possible to do so. Although I dont have IIS 5 but I have faced the same problem in IIS 6. IIS 5 and IIS 6 does not have any inbuild support for extension .XAP and so does not support Silverlight by default. To make it support .XAP we must have to add MIME type in IIS.
For Adding MIME types in IIS server, follow below mentioned steps:
- Click Start, select Programs, and then click Administrative Tools.click Internet Services Manager
- Right-click on the domain name and Open your Web Site properties.
- On the HTTP Headers tab click MIME Types.
- In the File Types window, click New Type to add a XAP Mime-Type and Click Ok
- Do iisreset