Feature control signaling can be transported from a handset to a network-based service platform when the handset is active on an existing call, using three-way calling and Intelligent Network (IN) capabilities to pass feature control information from the user device to a network-based service platform. Although Wireless Intelligent Network (WIN) standards do not support mid-call triggers, handset emulation of three-way-calling (3WC) behavior allows a handset to send a digit string (representing a particular feature-related event) to a network-based service platform (in the context of a pseudo-3WC). Mid-call communications can be accomplished in this manner, allowing a network-based service platform to interpret and take action based on the received digit string, prior to releasing the additional call leg associated with the pseudo-3WC attempt. WIN mechanisms can also be used to send feature control signals from a network-based service platform to a handset. These mechanisms can be used to promote consistent service offerings for users who are served by networks that are comprised of different technologies. These mechanisms can also be used to help operators transition their networks to support emerging network technologies.