Apologies, I didn’t mean to be the first (honest!), but this post is just to advise any interested radio users that as well as using PACTOR 1, 2, 3 or 4 the Cadet Forces’s HF Mailbox can now be accessed using a new mode - WINMOR.
The advantages of WINMOR is that it’s a sound card mode (so no PACTOR modem is required) and uses the same sort of PC>Radio interface that you would use for PSK-31, etc.
The software is free (well, apart from a subscribe ‘nag’ screen 
and is proving to be much faster than an old PK-232 or KAM box.
For techies, the problem with the radio’s transmit/receive changeover time when using old Clansman equipment with PACTOR (changeover typically <25mS) is not a problem when running WINMOR (changeover <100mS).
If you didn’t know, Cadet Forces’ users of the HF Mailbox can send/receive e-mails to/from any ‘Internet’ address - anywhere in the world - via HF radio.
So will your cadets be the first to ‘Tweet’ using HF radio? Sorry, the first HF SMS ‘texting’ was done a long time ago 
Details of the new mode can be found here The Winlink Book of Knowledge | Winlink Global Radio Email
Currently, there’s a couple of squadrons having a play with it and I can put you in touch with them for help, advice, chat, etc.