Have you tried this? This is from the 2050 softphone install guide. I haven't done much with the 2050's lately and I didn't realize it changed on the BCMs.
Licensing using the BCM HTTP server
The simplest method of licensing an Avaya 2050 IP Softphone is through the BCM HTTP
licensing server. License files are served from the BCM to the Avaya 2050 IP Softphone,
unlocking the softphone and enabling full functionality. License files are specific to each
installation of the Avaya 2050 IP Softphone.
Using this licensing method, you must generate a license for each Avaya 2050 IP Softphone that
you install. The Avaya 2050 IP Softphone must be installed on a PC and you must obtain the
required licensing files from your keycode supplied before you start this procedure.
Licensing using the BCM HTTP server is part of node-locked licensing methods. The Avaya 2050
IP Softphone uses two types of licensing methods: server-based licensing and node-locked
licensing. Node-locked licensing can be applied to the Avaya 2050 IP Softphone by licensing
using the BCM HTTP server.
1 In the Business Element Manager Configuration tab, navigate to Resources > Telephony
Resources.
2 In the Configured Device column of the Telephony Resources table, select IP Sets.
The Details for Module panel appears below the Telephony Resources table.
3 In the IP Terminal Global Settings tab of the Details area, click Upload.
The Import Files dialog appears.
4 In the Import files window, click Browse to locate the licensing files obtained from your
keycode supplier.
5 Select all the i2050 licensing files obtained from your keycode supplier.
6 Click Select files.
7 Click OK.
The files upload to the BCM and appear in the IP clients configuration files area.
8 Configure the Avaya 2050 IP Softphone to search for the files on the BCM. In the 2050 IP
Softphone Settings window, click Server.
9 In the Provisioning Server field of the Server panel, ensure the Protocol is set to HTTP and
that the URL field contains the location of the BCM.
10 Click OK.
You can now register the phone.