express315,
If you have been living overseas within the last 5 years you will need an original letter from the people who issued you your security airside pass.
This letter should state that you have had some sort of security check done and how long you held that pass for.
You will also need to provide original bills(hydro,phone,cable,etc) to prove that you were actually living in that country.
You have to prove where you were living with this evidence. Its not written anywhere in the Transport Canada rules, even when they quote the rules and you read it, its not there.
The main reason for not getting a airside pass is because the "Special Unit" branch in Ottawa will not conduct overseas enquiries on your behalf any more.
Most guys go to CSIS and RCMP gett letters and still get refuses a pass, this is because CSIS and RCMP only do Canada in their investigations.
As long you have original letters from the guys who issued your pass in the foreign country you worked in and you kept some original bill with your name and address on it you should have no real problems.