According to the documentation, Studio Enterprise Edition 6.0 supports several Language Environment (LE) commands, such as CEELOCT and CEESECS, but any attempt to call them fails with program not found.

These LE commands or modules are resolved in LE370.LBR, so the program that will call these modules will need to be compiled with the directive INITCALL(LE370.LBR). In other words, LE370.LBR module has to be loaded in memory prior to call the LE modules.