dashbuilder: Static data set definitions in WEB-INF/datasets dir not loaded on JWS3 (tomcat 8)

Description of problem:
When business-central is deployed on JWS3 in tomcat 8, Static data set definitions (see attachment) in WEB-INF/datasets are not loaded.

This setup is working correctly on EAP and in JWS2 (with tomcat 7) (i.e. those 3 data set definitions appear in Data Sets perspective > D.S. Explorer)

But when I do similar setup on tomcat8 (EWS 3) the data set definitions are not found/loaded and there are no log messages from DataSetDefDeployer class, which is responsible for scanning the dataset deployments dir.

Version-Release number of selected component (if applicable):
BPM Suite 6.2.0 ER4

How reproducible:
Always

Steps to Reproduce:
1. Setup BPM Suite 6.2.0 on EWS 3 (tomcat8).
2. create directory 'deployments' in tomcat8/webapps/business-central/WEB-INF/
3. copy all files from the attachment to this directory
4. Start tomcat using tomcat8/bin/catalina.sh run

Actual results:
The data set definitions are not loaded in UI. No error messages in the logs

Expected results:
The data set definitions should be loaded and should appear in Data Set Explorer in Data Sets perspective.