When creating a script for a table, Toad fails to include the script to create triggers associated with the table if the trigger does not belong to the same schema.
A. using schema browser | select a table | select the script tab (or right click Create Script)
B. using Database | Optimize | rebuild table
Individually create scripts for those missing triggers and include them into the the script manually.
Waiting for fix in a future version of Toad for Oracle.