By the sounds of it, you are wanting to configure port forwarding to access the PTZ camera on the LAN.
This is explained in document QN4, here: http://www.digi.com/support/productdetail?pid=5499&type=documentation
However, in the UK, assuming you are using the APN general.t-mobile.uk then your T-Mobile SIMs will be allocated a private IP address. In this case port forwarding is not going to be suitable by its self.
In this situation, you will need the MR2110 to build a VPN to another router on the internet that does have a public IP address. Then you will be able to send traffic to the router on the public address and forward traffic over the VPN to the MR2110 and the PTZ camera behind it.