Hi Layla,
There is a recipe in one of the "Top Secret" cookbooks for Outback Grilled Shrimp on the Barbie. The seasoning blend used is:
1/2 t salt
1/4 t garlic powder
1/4 t onion powder
1/4 t black pepper
1/4 t chili powder
1/4 t sugar
1/8 t cayenne pepper
dash ground allspice
Squeeze lemon juice on 6 large shrimp. Brush with 1 tablespoon melted butter and lightly coat with the seasoning.
Hope this helps! Happy Grilling!