You can always cut your existing card down to match the nano-SIM used by the iPhone 5. However, this isn't without risk, as you may end up damaging your SIM card and needing to have it replaced.The best way to cut SIM cards is using a punch cutter li...
No, it shouldn't be this difficult. You seem to be lucky - successfull activation of 2 SIM cards. If that was only the case here. I'm having issues with my 2 cards (1 partially resolved, 1 a current pain).