Populate Schema Name Dynamically

We are designing a server where functions and procedures are to be kept in a single database. Our other databases will call these functions. The functions will need to reference tables in the schema being called from. Is it possible to pass a schema name to a function? If so, then how?

I tried passing something like:


CREATE FUNCTION [dbo].[getPaymentReceived2](@inSchema CHAR(30), @inAraccountid CHAR(15), @inInvoicestart SMALLDATETIME)

RETURNS MONEY

AS

BEGIN

DECLARE @outAmt money

DECLARE @arinvoiceid char(15)

SET @arinvoiceid = (SELECT ai.arinvoiceid

FROM @inSchema.dbo.arinvoice ai

WHERE ai.araccountid = @inAraccountid

AND ai.invoicestart = DATEADD(month, - 1, @inInvoicestart))

I get an incorrrect syntax error.