EWM 6.0.6.1 Delete sources from RTC doesn't always delete all files from zOS datasets

This happens in a complete 6.0.6.1 environment. So server, client and BTK all have v 6.0.6.1. When I delete a source from RTC, the build-process should delete all files known in the build-map from this source. For a cobol-source, we have the source in COBB, the listing in LSTCOB and the loadmodule in MODB. But when a dataset is locked in anyway, no deletion is possible. In our OA environment I get three members in datasets when building the source: ONE.cbl, SYSTEM.OA.M.COBB(ONE, SYSTEM.OA.M.LSTCOB(ONE) and SYSTEM.OA.M.MODB(ONE). The dataset SYSTEM.OA.M.MODB is not in any CICS at the moment. When I do move this source to R, the file gets built into SYSTEM.R.* datasets. The SYSTEM.R.M.MODB is in a CICS that is running. Just building is no problem, the loadmodule is refreshed. When I do delete ONE in OA, SYSTEM.OA.M.LSTCOB(ONE), SYSTEM.OA.M.COBB(ONE) and SYSTEM.OA.M.MODB(ONE) are deleted. When I move the workitem with this delete to R and I do a build, SYSTEM.R.M.COBB(ONE) and SYSTEM.R.M.LSTCOB(ONE) are deleted, but SYSTEM.R.M.MODB(ONE) can't be deleted. Build gives no errors, but when looking at the build.log, you can see that the load module couldn't be deleted. Promoting to the next level S, SYSTEM.S.M.MODB(ONE) is deleted as this dataset is not in a CICS. Is there another programmatic way to resolve this?