I don't think the use of trunk-access codes is available in 3.3. Some people try to simulate this feature using translation patterns/route patterns. But, as you have noted, this workaround has some drawbacks. Mainly, it doesn't take long for users...
I believe that the telco is saying that if you are attempting a call, you either identify the call as international by prefixing the 011 digits OR by sending the numbering type as 'International'. I don't think you can do both.Regards.