The SVN changlog only shows changes in external projects.
Changes in the main project are not logged (The build IS triggered corretly.

polling log shows:
<server>/Shared/tools/trunk is at revision 670
<server>/project/trunk is at revision 1180 (changed from 1179)
<server>/shared/library/trunk is at revision 1175
<server>/otherproject/trunk is at revision 1170

revision list shows
<server>/Shared/tools : 670
<server>/project/trunk : 1180
<server>/shared/library/trunk : 1175
<server>/otherproject/trunk : 1170
No Changes.

and below that: "Started by an SCM Change".

If we do make a change in 'library' it is showing the changes correctly.