AdvancedHMI is designed to be open enough to allow you to develop your own components. We cover this in our advanced training sessions.
As for using the DLLs, the software licensing does not allow pieces to be pulled out of the package to be used in other applications. The software license intent is to create applications and extend the package and distribute as a complete package. The purpose of this licensing model is to keep AdvancedHMI a self-proliferating development software package.
As for logging data, it is not too complicated to achieve with a little bit of VB code. There are multiple ways to achieve this. One is to add a BasicLabel to a form and also add a timer that will get the Text property from the BasicLabel on regular intervals and store it in a database.
You can also add a timer and in the Tick event handler, read the data directly from the PLC using the ReadAny or ReadSynchronous methods of the driver.