Creating a nullable<T> extension method ,how do you do it?

I have a situation where I need to compare nullable types.
Suppose you have 2 values:

int? foo=null;
int? bar=4;

This will not work:

if(foo>bar)

The following works but obviously not for nullable as we restrict it to value types:

public static bool IsLessThan<T>(this T leftValue, T rightValue) where T : struct, IComparable<T>
{
       return leftValue.CompareTo(rightValue) == -1;
}

This works but it's not generic:

public static bool IsLessThan(this int? leftValue, int? rightValue)
{
    return Nullable.Compare(leftValue, rightValue) == -1;
}

How do I make a Generic version of my IsLessThan?

Thanks a lot