Ok, set up below. Aux 1 will give a 2 second pulse when DI5 is turned on, Aux 2 will give a 2 second pulse when DI5 is switched off. Aux 2 will also give a 2 second pulse at key-on to make sure the valve? is closed. If you dont want a pulse at key-on like this then you can add a 3rd condition "RPM>500".
As Simon mentioned, you will need to wire the output of the potentiometer to a spare analog input (with the other two pin on the pot wired to +5 Volts and sensor ground). AN Volt 4 is shown in the example below. Then select a spare Cal, I use 4 as it is a 2 point linear cal instead of a table.
Next, in the cal settings choose % as the output unit. IT doesn't have to be %, you could leave it as 0-5 Volt raw.
I would start with open loop boost control, as you will need to find out what duty cycle is required to achieve a particular boost target.
In the wastegate %DC table, select the an volt input as the y axis and populate the table with the %DC required for each boost step required. In the example above I have used 50% duty cycle as maximum boost.
That is the easy bit done! I would suggest looking at the help file for information about setting up boost control and when you are happy with the open loop mode, progress on to closed loop boost as this will give you more consistent boost levels which will be met and maintained by the closed loop algorithm.