I've been getting into using the webservices API and enjoying the features I can use

I have successfully used GetServiceByName to return a service and then used the output of that in GetElementsForService to get an array of the elements associated with the service.

I am trawling through the methods trying to find one where I can add or remove elements for a service but cannot find what I am looking for.

Additionally I am trying to find the Visio File Name associated to a service but the GetServiceByName only has a Boolean of HasVisio but not the filename, and any of the GetVisioXXX functions seem to just output a PNG and not advise of the filename of the Visio.

I was delighted though to find AssignVisioFileToService

My question is there any way to modify the element service associations (ie: remove elements from one service and add them to another service) and get the filename of a visio assigned to a service through the Web Services API?