Now the problem is that %param-Software% gives me the distinguishedName and that is not really helpful.
This behavior is by design. Value references for Custom Command parameters of AD object picker type always resolve into distinguished names. Unfortunately, there is no possibility to obtain values of other properties of the object selected in the parameter using value references.
When I use %description% I get the description from the user object. Is there a way I can output the description propertie from the target-object?
In custom action descriptions, value references always resolve into the values of corresponding properties of the object for which the Custom Command is executed. For example, if a command is executed for user John Smith, value reference %fullname% will resolve into John Smith, not the full name of the user who initiated the command execution.
If you face a different behavior, please, post here or send us (support[at]adaxes.com) with the exact custom action description you are using and all the possible details regarding the behavior.