Pulse Mini wont let u-sim work!

[Guest kosborn2]

I have an o2 sim card and i use a u-sim (computer chip cut into my o2 sim) so that I can use o2 without unlocking my pulse, BUT it wont work on the mini!? Have they programmed this into the mini so that it blocks these cards? I am going to pay for an unlock for my mini but i'm just confused as to whats wrong with the u-sim!! Any idea's? Cheers