Basically protocal i.e. SSL3 or TSL Doesn't depend on application but mainly depends on the Framework
they built on . So in your Question i couldn't find the much information about the Framework on which your applications built on.
My intention is to tell my application users to use tls and not to use
ssl3 because of poodle vulnerability.
Your users might be using your Webservices or the asmx service that was written and deployed in your server , so i would say that can't ask the user to change their protocal because its mainly dependent on the framework they are using i.e the framework they built on. so in order to achieve your goal try to by default make your applications run on .Net Framework 4.5
and assign to use the tls
as follows
ServicePointManager.SecurityProtocol = (SecurityProtocolType)192
Please find that Following SecurityProtocalType Refernce
Ssl3 = 48,
Tls = 192,
Tls11 = 768,
Tls12 = 3072,
In this way instead of telling your Users , you are actually making to use the tls
when they are requesting your services