Issuetracker Services Tag not shown

Hi,

I want to work with a Issue tracker but the node "Issue trackers" is not shown 
any more in the Services Tag.

If I try to install the Redmine module I get the error message:

>Some plugins require plugin Issue Tracking to be installed.
>The plugin Issue Tracking is requested in implementation version 
>201306052037.  The following plugin is affected:       RedmineNB

But I can not see an Issue-Tracker implementation module in the update center.

I have switched to NB 8.2. In earlier version it works finde but I am not sure 
if this is a problem of the version. 

Any ideas?

best regards
Oliver