VS 2015 Selecting cyphers for TLS 1.2

Hi there!

Probably very simple. I set ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 to be compliant with the authority with which the application communicates. But now, the authority is requesting that the cypher suite be limited only to particular cyphers e.g. DHE-RSA-AES256-SHA, RSA_WITH_AES_256_CBC_SHA, etc. How can I specify the supported cyphers in the VB.net code?

Thanks!