well i'm not sure if you are using the "number" as a boolean, but if you are you could define it as a Nullables.NullableBoolean.
Otherwise there are NullableInt16, NullableInt32 and NullableInt64.
Code:
using Nullables;
public class MyClass {
private NullableBoolean myNumber;
public NullableBoolean MyNumber {
get { return this.myNumber; }
set { this.myNumber = value; }
}
}
Code:
<class name="MyClass>
<id></id>
<property name="MyNumber" type="Nullables.NHibernate.NullableBooleanType, Nullables.NHibernate" />
</class>