Hi The-MeLLeR,
Unfortunately, the documentation about it isn't ready yet, also we want to publish the common implementation part into open-api. But for now you can start with the following interfaces:
SIssueProvider - represents a single provider (connection) to the issue tracker, extends IssueProvider;
IssueProviderFactory - a factory for creating providers;
All interfaces are in jetbrains.buildServer.issueTracker package. You may need to implement several more optional interfaces, but these are main.
A brief explanation can be found in the javadoc to these interfaces.
As for the UI part, you need to add a special JSP: <plugin>/admin/editIssueProvider.jsp, which will be loaded on admin page for creating/editing providers.
Basically that's all.
---
Maxim
