Questions about SLA

I have successfully configured Shared Line Appearances with asterisk 1.4-r59573 and two GXP2000 phones but few things are not straight to me.

If i set barge=no and i put a call on hold i can’t reconnect to the trunk from any phones, i must stop and restart asterisk. And if the remote party hangup the SLAtrunk is hanguped but the hint remains OnHold. Perhaps i have misunderstood the meaning of this option, but in the doc says “If this option is set to “no”, then no station will be allowed to join a call that is in progress” but if it’s on hold?

In all traditional key systems a user can connect to a SLA only if another user put on hold the line.

When i put on hold, no moh is hear on the trunk, only silence, it’s normal?

How can i transfer a call on SLA to an extension that is not defined in sla.conf or have not blf?