Adding User Define fields together

This is driving me crazy! The SQL Statement refenced is shown at the end of this email.

When I try and run the statement, an error is raised saying that Undrawn_GT5MIL_LE365Days is invalid (likewise for Undrawn_LE5MIL_LE365Days). From what I can gather, it is saying that I cannot include a User Defined variable in another argument. This is unlike Access. Any suggestions?

SQL View......

SELECT TOP 100 PERCENT QRY_FacNew_Term.Category, QRY_FacNew_Term.Fac_No, QRY_FacNew_Term.Client_Number, QRY_FacNew_Term.Client_Name,

Undrawn_GT5MIL_LE365Days = CASE WHEN Undrawn_CDN >= 5000000 AND Term <= 365 THEN Undrawn_CDN ELSE 0 END,

Undrawn_GT5MIL_GT365Days = CASE WHEN (Undrawn_CDN >= 5000000 AND Term > 365) OR

(Cr_Limit_CDN IN (0, 1)) THEN Undrawn_CDN ELSE 0 END, [Undrawn_GT5MIL_LE365Days]+[Undrawn_GT5MIL_GT365Days] AS Total

FROM dbo.QRY_FacNew_Term

WHERE (Exclude <> 'Y')

ORDER BY Category, Client_NameUse brackets if name includes space:

[drawn_GT5MIL_LE365Days ] = CASE WHEN Undrawn_CDN >= 5000000 AND Term <= 365 THEN Undrawn_CDN ELSE 0 END,