Everything that ActiveX will let you modify in Windows Media Player can be changed by using a property or invoke node with reference to a Windows Media ActiveX Object. You can browse all of these by opening the class browser and changing the object library to ActiveX>>Windows Media Player Version 1.0. You may have to go to select type libraries in order to select it. This will present you with a list of different ActiveX methods and properties that you can change or read. You should be able to find the options you need there.
Note that some properties will return another handle, which can in turn be referenced to change a property of that handle. For example, if you read the Settings property, then use the handle returned as an input to another property node, more options will present themselves such as mute or rate.