How specify foreign key column name in model?

In a model declaration I can specify the name of the primary key column with

set_primary_key "CUSTOMER_NUMBER"

How can I set the name of a foreign key column that does not conform to the RoR naming convention. Does the following work?

set_foreign_key "CUSTOMER_NUMBER"

If not, how can I specify the name of the foreign key column? Thanks.

Ignore the question. I found the answer.