Thanks a lot. It worked.
However, I had partitions without a label and I therefore used ID_FS_UUID instead:
1) run "blkid" and take note of partition uid's;
2) Add the following line to 95-udevil-mount.rules (just under the one with ID_FS_LABEL):
ENV{ID_FS_UUID}=="youruid1|youruid2|...", GOTO="exit"