There are three ways how you can accomplish your task:
Adaxes SPML provider
Adaxes implements an SPML provider that can be used to synchronize changes with Active Directory. If the HR system of your customers can automatically send SPML requests via the SPML v.2.0 protocol, you can configure the HR system to send requests to Adaxes SPML provider whenever a user is created, modified, deleted etc in their HR system. The SPML provider will translate the SPML requests into requests to create, update, delete etc AD objects that will be sent to Adaxes service.
For more information, see the following help article: http://www.adaxes.com/help/?SPMLSupport ... iders.html.
Adaxes ADSI provider
Adaxes also implements ADSI interfaces that can be used to access Active Directory via Adaxes service. The interfaces supported by the ADSI provider can be accessed from any programming language that supports COM, such as VBScript, PowerShell, C++, and .NET languages like VB.NET and C#. If their HR system implements a scripting language that supports COM, you can use it to access Adaxes service by means of Adaxes ADSI provider to perform the necessary operations in AD.
For more information, see the following article in our SDK: http://www.adaxes.com/sdk/?WritingAdsiScripts.html.
For sample scripts with examples of how to access and use Adaxes ADSI provider, see section Sample Scripts in our SDK: http://www.adaxes.com/sdk/.
Import data from CSV, XLS, XML etc
If their HR system can generate reports in the CSV, XLS, XML formats, you can create a Scheduled Task that will import information from the files generated by the HR system and perform the necessary changes in AD. In this case, you can also use scripts. For an example of a Scheduled Task that imports new users from a CSV file, see the following tutorial: http://www.adaxes.com/tutorials_ActiveD ... romCSV.htm.
As for the 'backlink' from Adaxes to the HR system, you can also use PowerShell scripts and export to files. For example, if the HR system has some sort of interfaces that can be accessed from external applications to trigger operations in the HR system, you can create PowerShell scripts that will access the interfaces from Adaxes and perform the necessary calls to the HR system. If the system supports importing from CSV or XML files, for example, you can create a PowerShell script that will export information on a user to a CSV file after the user is created, updated, added to a group etc in AD.
Then, you can create Business Rules triggered after the user is created, updated added to a group etc that will launch the PowerShell scripts with the help of the Run a program or PowerShell script action. For an example of such a Business Rule, see the following tutorial: http://www.adaxes.com/tutorials_Automat ... ngUser.htm.
Or, alternatively, you can create a Scheduled Task that will export the information on users that they need in their HR system on a periodical basis.
If you need assistance with the scripts, we can help you or even write them for you.