A computer-implemented method for configuring a communication system comprising a Private Branch Exchange, PBX, system and a Service Management Platform, SMP, connected to and communicating with the PBX system, to extend the features of enterprise telephony to an enterprise-associated mobile communication device belonging to a user, the method comprising: configuring the PBX system to respond to a configuration telephone number by routing call control for the configuration number to the SMP; determining an enterprise extension associated with an enterprise account in the domain of the SMP; querying, by the SMP, an enterprise user database with a user identifier of the user and receiving, by the SMP, an enterprise extension number associated with the user in response; sending, by the SMP, an e-mail message to the device, whereby the message comprises the enterprise extension number of the user and an authentication token, and whereby the message directs the device to call the configured configuration telephone number; receiving (642, 740), at the PBX system, the call to the configuration telephone number; routing (652, 750), by the PBX system, the call to the SMP and establishing a two-way communication between the device and the SMP; receiving, at the SMP from the device, the enterprise extension number previously sent by e-mail to the device; receiving, at the SMP, from the PBX the particular PBX system port over which the two-way communication occurs; directing (682, 780) by the SMP the device to communicate the authentication token previously sent by e-mail to the device; receiving, at the SMP from the device over the established two-way communication, the authentication token; and upon receipt, by the SMP, of an authentication token equivalent to the authentication token sent by e-mail, associating the enterprise extension number with the determined PBX system port, thereby configuring the given SMP for the given enterprise-associated mobile device. configuring the PBX system to respond to a configuration telephone number by routing call control for the configuration number to the SMP; determining an enterprise extension associated with an enterprise account in the domain of the SMP; querying, by the SMP, an enterprise user database with a user identifier of the user and receiving, by the SMP, an enterprise extension number associated with the user in response; sending, by the SMP, an e-mail message to the device, whereby the message comprises the enterprise extension number of the user and an authentication token, and whereby the message directs the device to call the configured configuration telephone number; receiving (642, 740), at the PBX system, the call to the configuration telephone number; routing (652, 750), by the PBX system, the call to the SMP and establishing a two-way communication between the device and the SMP; receiving, at the SMP from the device, the enterprise extension number previously sent by e-mail to the device; receiving, at the SMP, from the PBX the particular PBX system port over which the two-way communication occurs; directing (682, 780) by the SMP the device to communicate the authentication token previously sent by e-mail to the device; receiving, at the SMP from the device over the established two-way communication, the authentication token; and upon receipt, by the SMP, of an authentication token equivalent to the authentication token sent by e-mail, associating the enterprise extension number with the determined PBX system port, thereby configuring the given SMP for the given enterprise-associated mobile device.