Are you using system OAI to talk to the 5000? If so, the command to tell ext 111 to call outside number 961-555-9000 would be
_MC,<invokeID>,111,89615559000 C/R
Invoke ID is a serial number you assign for this one-time transaction...system will return success confirmation referencing this number
If you're not talking OAI and your app can't interact with phone buttons your best bet is probably to write a macro to work through UCA, UCX, Xarios or Connection Assistant, basically pasting the number in and initiating a dial.