I can see from the dicussions various posts about resetting a voicemail PIN through CCA and it not being possible and you need to use the GUI at 10.1.10.1.
I have tried to browse to the GUI and it doesn't work, if i try to ping 10.1.10.1 i get a response from the IP of the UC540. I know you can do it via CLI:
UC540#service-module integrated-Service-Engine 0/0 session
se-10-1-1-117# user (username) pin (value)
However when i try the service-module integrated-Service-Engine 0/0 session command it errors with connection refused by remote host.
Cannot reach CUE is due to routing problem, e.g. you internet router knows nothing about 10.1.10.x
For CLI access, do a 'session clear' before 'session'.