Changing a Password Server user password from Win client

I have searched everything I can find and can find no reference to this problem -- perhaps someone can help -- I have a OS X 10.2 server setup to provide a shared netinfo domain and use open directory and the password server to authenticate users, this all seems to work fine ... However, I can not figure out how a user on a windows client machine can change the password that is stored at the password server for his own account. Does anyone know how, or if this can be done?