You got me confused for a second when you mentioned there was not instructions for replacing the MSA ( Maintenance Station Assembly ).
The capping station it is a part of an assembly and you are right, the service manual does not show how to replace it but, if you have the exploted view diagram you should be able to take it apart, just be careful when taking apart the capping station do not want to brake the plastic tabs that hold it in place, very easy stuff.