I'm new to Salesforce development and I've been tasked to add some functionality.
We have installed an app (specifically "Zendesk for Salesforce") which syncs data from Salesforce to Zendesk via a REST API.
The app contains API authentication details.
What I would like to do is extend the app (managed package) to send some more data to Zendesk.
Ideally I would like to be able to call functions/classes from the app instead of using the base HTTP classes. If that isn't possible I would like to access the authentication details stored in the app so that they are only in one place.
Is this possible, or am I going to have to duplicate some of the access and functionality of the managed package?
Hope that makes sense, I'm on a bit of a crash course.