CeTigges,
Belize suffers from an identity crisis of sorts. While it's technically part of mainland Central America, it's also aligned with the Caribbean countries. For example, Belize is part of CARICOM, the economic and trade organization that represents the Caribbean area, so Belize wasn't included in CAFTA[1].

On the other hand, Belize might be considered an outsider to the Central American system because they don't hold regularly scheduled revolutions, but that's just conjecture on my part.

Dan

Note 1. CAFTA is to Central America what NAFTA is to North America.

"Facts are the enemy of Truth"
Don Quixote