Incorrect Syntax near $38.82.0 in Query

Hi all,

I have created a query for FMS in an UDF at AR Invoice to display total tax amount for certain tax group but it keeps saying "1). [Microsoft][SQL Server Native Client 10.0][SQL Server]Incorrect syntax near '$38.18.0'. 2). [Microsoft][SQL Server Native Client 10.0][SQL Server]Statement 'User-Defined Values' (CSHS) (s) could not be prepared."

$38.18.0 - VAT Code

Please check what is the problem with the query below:

SELECT Sum(T0.[VatSumSy]) FROM INV1 T0 WHERE $[$38.18.0] in ('SR','DS','AJS')

Thanks,

Leng