shtml files in WSAD test env

[samasamajam]

my web application has shtml files. In WSAD(5.1.2) test environment, when i try to acces the shtml file, my browser prompts me for required action (to download, or open with default application). Could someone tell me the required configuration changes to enable my test environment to serve shtml files.
I know it is not a problem with browser as I can view the shtml files on other sites on the internet.