What is the difference between the asset type ESB service and service in Centrasite

Hi ,

We have started implementing centrasite in our project recently.
And to start with we have thought to use it as a repository of services we have created in Webmenthods developer, So I would like to map all the flow services created in Wm to the asset type in centrasite
So Should i use a ESB service or Service asset type for this purpose.
Please suggest and can any one tell me the actual difference between them