Well, I'm glad that worked. As for me, I still have a loop back problem.
I have a string quartet configuration set up in MIR 1.3 trial, and instruments sound very good in MIR (superb product!), as fas as this is stand alone. Problem comes when connected with Sibelius.
I have defined a couple of midi ports in LoopBe30 (but une only 1 for now) and disabled the "Enable Shortcut Detection".
In Sibelius 6.2, I have loaded a playback configuration that uses the VE special edition sound set on Internal Midi device. The channel numbers of the string instruments match those defined in MIR, but I didn't define any "program number".
In Sibelius preferences for Input devices, I can see all the internal midi devices, which are ticked enabled. I have also unchecked "midi thru" AND "Echo notes when in background".
In Sibelius I then go to the end of the score and click on, say, the last note of the cello. I clearly hear the cello in MIR (so it goes from Sib to Mir ok) but Sibelius then freezes a moment and then automatically inserts a couple of pages worth of very low notes -- as if some internal input had occured. I usually can Ctrl-Z the score back to its original sstate (undoing all the inserts) but sooner or later Sibelius freezes.
I must have overlooked something about loop back but I cannot identify what it is. Any ideas?