Some one suggested this function works

ALTER function [dbo].[ConvertBigIntToVarBinary1](@param bigint)

returns varbinary(1000) AS

begin

declare @iPower int;

declare @result varbinary(1000);

declare @powerOf2 bigint;

set @result = 0x;

set @powerOf2 = 1;

set @iPower = 0;

while @powerOf2 <= @param

begin

set @result = @result + CAST(@param / @powerOf2 % 2 AS binary(1));

set @iPower = @iPower + 1;

set @powerOf2 = power(2., @iPower);

end

return @result

end

Although I dont see much advance of it plus it fails to convert the max bigint value for some reasons

SELECT dbo.ConvertBigIntToVarBinary1(9223372036854775807)