OK, yes, it seems it is now OK to virtualise tapes but only a few drives are supported and as yours shows as "Other SCSI Tape Drive" I guess it is not one of the few.
http://www.redbooks.ibm.com/redbooks/pdfs/sg247590.pdf
Page 23:
Supported tape drives at the time of writing are:
Feature Code 5907 36/72 GB 4 mm DAT72 SAS Tape Drive
Feature Code 5619 DAT160: 80/160 GB DAT160 SAS Tape Drive
Feature Code 5746 Half High 800 GB/1.6 TB LTO4 SAS Tape Drive