Multiple WHENs in triggers

Hi all,

I'm trying to put in a series of conditionals into a trigger, along the lines of

--
CREATE TRIGGER UpdateSaleItemDescription AFTER INSERT ON SaleItem

WHEN NEW.SaleItem_ID='7'
BEGIN
UPDATE SaleItem SET SaleItem_Description='This is seven' WHERE SaleItem_ID=NEW.SaleItem_Id;
END;

WHEN NEW.SaleItem_ID<>'7'
BEGIN
UPDATE SaleItem SET SaleItem_Description='This is not seven' WHERE SaleItem_ID=NEW.SaleItem_Id;
END;


INSERT INTO SaleItem(SaleItem_TaxRate) VALUES('0');
INSERT INTO SaleItem(SaleItem_TaxRate) VALUES('0');
--

(obviously simplified for ease of description here).

But this isn't working - I get a syntax error near WHEN (the second one). If I remove the four lines starting WHEN NEW.SaleItem_ID='8' then it works ok.

Can I use a SELECT CASE statement here? If so, what's the syntax? I can't believe that SQLite only allows only one trigger with only one WHEN per action... can it?

Thanks in advance,

Hamish