How properly import mailboxes from Mozilla Mail?

[mpiktas <mpiktas delfi lt>]

Hi,

I'm thinking of using Balsa instead of Mozilla Mail. One thing is 
holding me back though. How properly import my mailboxes from Mozilla 
Mail?  Just copying them seems to do the trick, but then read messages 
appear as unread again.  I tried to compact the folder in Mozilla Mail, 
but this did not help.

This is only the minor anoyance, and I can live with that. The most 
anoying thing, that Balsa is really slow opening large imported 
mailboxes. I tried to open mailbox with more than 5000 letters and it 
took Balsa 27 seconds to do that and it eats up all processor time. If I 
choose Flat Index from menu Balsa again uses 100% of processor, and I do 
not wait till it finishes, because everything takes more than 3 minutes 
and I suspect then that Balsa freezes. The only way to stop this 
operation is to use killall balsa.

Is this Balsa issue, or is this Mozilla Mail creating bad mailboxes?

Thanks for your answers

Mpiktas