[HECnet] Links across volumes? (FILE/ENTER won't work)

I just added a disk to solar, DKA100: and have created a directory called DKA100:[DECUSLIB] on it. I want to link it into DKA0:[SYS0.DECNET] as DKA0:[SYS0.DECNET.DECUSLIB]. However: $ SET FILE/ENTER=DKA0:[SYS0.DECNET]DECUSLIB.DIR;1 DKA100:[000000]DECUSLIB.DIR;1 %SET-E-ENTERR, error entering DKA100:[000000]DECUSLIB.DIR;1 as DKA0:[SYS0.DECNET]DECUSLIB.DIR;1 -RMS-F-DEV, error in device name or inappropriate device type for operation Here's what's in DKA100: $ dir dka100:[000000] Directory DKA100:[000000] 000000.DIR;1 0.50KB 7-FEB-2015 00:26:49.44 BACKUP.SYS;1 0KB 7-FEB-2015 00:26:49.44 BADBLK.SYS;1 0KB 7-FEB-2015 00:26:49.44 BADLOG.SYS;1 0KB 7-FEB-2015 00:26:49.44 BITMAP.SYS;1 5MB 7-FEB-2015 00:26:49.44 CONTIN.SYS;1 0KB 7-FEB-2015 00:26:49.44 CORIMG.SYS;1 0KB 7-FEB-2015 00:26:49.44 DECUSLIB.DIR;1 0.50KB 7-FEB-2015 00:27:23.74 INDEXF.SYS;1 2.03MB 7-FEB-2015 00:26:49.44 SECURITY.SYS;1 0.50KB 7-FEB-2015 00:26:49.44 VOLSET.SYS;1 0KB 7-FEB-2015 00:26:49.44 Total of 11 files, 7.03MB On *NIX I'd use a symbolic link - what's the VMS solution?