Question: Integration with Units Error

This is my first attempt at trying the units feature within Maple. I have had mixed results. I have a function defined that gives me values in [cal/mol/K], which is correct. But when I try to use this as the integrand in an integral definition it does not want to solve. I cannot determine what the problem is.

I thought that I possibly needed to define units in the integral expression, but this just produces more errors or locks-up Maple completely. (Side note: When Maple locks-up, the "interupt current operation" toolbar often does not correctly kill the operation, and I am forced to restart Maple :/)

As I have the problem defined, I should get the following result:

T__sys= 64.47487 [K], should get me HIG(T__sys) = -19682.7 [cal/mol].

See attached: EnthalpyTrace_-_Integrating_with_Units_Error.mw

Any help or insights would be greatly appreciated.