Java's MSCAPI from Web Applett Error?

I am developing an application that uses Java's Crytographic Extension, more specifically MSCAPI, to sign a file using a user's private key all from a web browser. I have been able to do this succesfully locally, but when i embed the class in a web page and try to access users keystore i get the following error: "no such provider: SunMSCAPI". Does anyone have any knowledge pertaining to the cause of this error?

The line of code that causes the error:

KeyStore ks = KeyStore.getInstance("Windows-MY", "SunMSCAPI");

Thank开发者_高级运维s

SunMSCAPI is only available in Java 6 as of today.