How to use the COLLATE in a JOIN in SQL Server?

Correct syntax looks like this. See MSDN.

SELECT *
  FROM [FAEB].[dbo].[ExportaComisiones] AS f
  JOIN [zCredifiel].[dbo].[optPerson] AS p

  ON p.vTreasuryId COLLATE Latin1_General_CI_AS = f.RFC COLLATE Latin1_General_CI_AS