Wrapped in a function and/or stored procedure, recursive CTE stops working

Question

This query builds an hierarchical tree from a single table with the typical 
value/reports_to_value columns. 
When running in SQL manager returns like 7 records (note i'm avoiding infinite 
loop by blocking top level value)
WITH c 
AS
    SELECT deptid, reports_to_dept
    FROM glo_tree
    WHERE deptid = '18538'
    UNION ALL
    SELECT t.deptid, t.reports_to_dept
    FROM glo_tree T  
    INNER JOIN c 
ON t.deptid = c.reports_to_dept
    where t.deptid <> '00001'
SELECT deptid  
FROM c 
However, the exact same query, if wrapped in a function and/or stored procedure, 
returns 0 records (no error message whatsoever)
CREATE FUNCTION [dbo].[checkDept] (@deptid varchar(16))
RETURNS TABLE
AS
RETURN
    WITH c 
    AS
        SELECT  deptid, reports_to_dept
        FROM    glo_tree
        WHERE   deptid = @deptid
    UNION ALL
    SELECT  t.deptid, t.reports_to_dept
    FROM    glo_tree T  
    INNER JOIN c 
    ON      t.deptid = c.reports_to_dept
SELECT deptid  
FROM c 
GO
CREATE PROCEDURE [dbo].[getDept] (@deptid varchar(16))
AS
    SELECT deptid
    FROM dbo.checkDept(@deptid)
Then call them like:
select * FROM checkDept('18538')exec getDept @deptid='18538'
Both return nothing

Answer 1

Thanks Patrick, i don't think it can do that, i call it like:
select * FROM checkDept('18538')exec getDept @deptid='18538'Just to make sure, i've changed the function like:WHERE ltrim(rtrim(deptid)) = @deptidStill the same thing