According to Page 23 of the 5.0.1 Release Notes, when you change the base profile to Lync, the Lync Device Update is supposed to be enabled by default.
|device.prov.lyncDevice UpdateEnabled||0 or 1||0 or 1||To enable/disable the Lync device update feature. If base profile is Generic, the default value is 0. If base profile is Lync, the default value is 1.|
This is the case when you change the base profile using the phone interface in the Settings -> Advanced -> Administration -> Network Configuration Menu
But when you use the Web UI the above parameter in the device config does not get set properly (stays equal to 0).
So if you are having problems getting your Polycom VVX to update properly, you might take a look at the device config and see how the above parameter is set.
Instead of just changing this parameter, I've chosen to Factory Default my phone and change the Base Profile to Lync using the phone interface. Just a little bit more comfort in case there are other parameters not being set properly.