Parameterized queries - works in Access but not SQLS2k?

I have an application where users can enter data into any (or all) of 6 search fields,
to produce a filtered query.

This works fine using my Access version(see code below),
but as SQLS2k cannot use "IIF", I tried to replace these bits with
"CASE/WHEN/THEN/ELSE" lines, which does not work with numeric fields
as these cannot be "wild-carded" in the same way as Access allows.

Can anyone suggest a way forward that does not involve coding all the
possible permutations of "SELECT" blocks driven by lots of nested "IF/THEN/ELSE"s?

Hoping you can help
Alex


PARAMETERS
CurrentType Text,
CurrentCategoryID Long,
CurrentProductID Long,
CurrentClientID Long,
CurrentContractID Long,
FromDate DateTime,
ToDate DateTime;

SELECT
tAudit.AuditID,
tAudit.ActionType,
tAudit.ClientID,
tClients.ContactCompanyName,
tAudit.ContractID,
tContracts.ClientRef,
tAudit.ProductID,
tProducts.ProductName,
tAudit.CategoryID,
tCategories.CategoryName,
tAudit.Acknowledged,
tAudit.ValueAmount,
tAudit.DateStamp

FROM (((tAudit
LEFT JOIN tCategories
ON tAudit.CategoryID = tCategories.CategoryID)
LEFT JOIN tClients ON tAudit.ClientID = tClients.ClientID)
LEFT JOIN tContracts ON tAudit.ContractID = tContracts.ContractID)
LEFT JOIN tProducts ON tAudit.ProductID = tProducts.ProductID

WHERE (((tAudit.ActionType) Like IIf(IsNull([CurrentType]),"*",[CurrentType]))
AND ((tAudit.ClientID) Like IIf(IsNull([CurrentClientID]),"*",[CurrentClientID]))
AND ((tAudit.ContractID) Like IIf(IsNull([CurrentContractID]),"*",[CurrentContractID]))
AND ((tAudit.ProductID) Like IIf(IsNull([CurrentProductID]),"*",[CurrentProductID]))
AND ((tAudit.CategoryID) Like IIf(IsNull([CurrentCategoryID]),"*",[CurrentCategoryID]))
AND (([tAudit].[DateStamp]) Between [FromDate] And [ToDate]));(tAudit.ContractID) Like IIf(IsNull([CurrentContractID]),"*",[CurrentContractID])
Mdaaa...
tAudit.ContractID = isnull([CurrentContractID],tAudit.ContractID)
???|||Thanks Buser - works fine - much obliged to you!

Regards
Alex