How do I check for division by zero and null to avoid -1.#INF in cells

How do I check for division by zero and null to avoid -1.#INF in cells.

WITH
MEMBER [Measures].[ZeroValuePerUnit] AS 0
MEMBER [Measures].[DivideByZero] As [Measures].[Internet Sales Amount]/[Measures].[ZeroValuePerUnit] ,Format_String = '#.#0'
MEMBER [Measures].[CheckDivByZero] AS IIF([Measures].[ZeroValuePerUnit] = 0, Null,  [Measures].[Internet Sales Amount]/[Measures].[ZeroValuePerUnit]),Format_String = '#.#0'
SELECT {[Measures].[Internet Sales Amount], [Measures].[ZeroValuePerUnit], [Measures].[DivideByZero], [Measures].[CheckDivByZero]} ON COLUMNS,
 [Customer].[Country].Children ON ROWS
FROM [Adventure Works]
WHERE([Date].[Calendar].[Calendar Year].&[2004]);

Result will be:

	Internet Sales Amount	ZeroValuePerUnit	DivideByZero	CheckDivByZero
Australia	$2,563,884.29	0	1.#INF	(null)
Canada	$673,628.21	0	1.#INF	(null)
France	$922,179.04	0	1.#INF	(null)
Germany	$1,076,890.77	0	1.#INF	(null)
United Kingdom	$1,210,286.27	0	1.#INF	(null)
United States	$3,324,031.16	0	1.#INF	(null)