There is nothing on the phone that directs you to a network, all data for network selection is on the SIM. This could just be a translation issue; your phone receives an operator id and translates it to an operator name. The translation table may reside on your phone but can also reside on your SIM. Maybe BASE is not in your Windows ROM, although I rather expect it to be in your Radio ROM. You might want to consider upgrading the radio ROM. It is recommended to use version 1.17 for the Hima.
Otherwise, if you live near the border, it might be that your Hima tries to roam on a Orange cell that is stronger than a BASE cell. You can recognize this by the triangle that appears next to the connection icon. Data traffic is always routed to a APN, also when roaming. In that case, you could roam on Orange but still use GPRS on the BASE APN.
Try selecting the network manually and see if BASE pops up, if not, it is only a translation error of the network name.