eScript question, hasOwnProperty

I am writing custom eScript code and need to determine whether or not an object has its own property. The compiler, however, complains that "hasOwnProperty" is not recognized. Can this be true? The Object.prototype.hasOwnProperty has existed in ECMAScript-262 since at least 1999!

So, two questions:

1) Does anyone know how to make a hasOwnProperty in eScript?

2) Does eScript allow extensions of native eScript objects?

Thanks in advance for any help.