gpart on macbook air

Hi all,

i installed CURRENT on a macbook air
(internal ssd as you know):
i noticed the following:

1. on freebsd, deleting a partition with gpart: say
gpart delete -i 4 ada0
dammage the osx boot.
of cours, booting with a backup disk and repairing the disk
make it functional again.

any light woukd be appreciated on this topic.

2. my gpart partitions table looks like this:
=>       34  490234685  ada0  GPT  (233G)
         34          6        - free -  (3.0k)
         40     409600     1  efi  (200M)
     409640  449218744     2  apple-hfs  (214G)
  449628384    1269536     3  apple-boot  (619M)
  450897920        256     4  freebsd-boot  (128k)
  450898176    1024000     5  freebsd-swap  (500M)
  451922176   38312543     6  freebsd-ufs  (18G)


no special mbr: planty of 00 and at offset 1be only the efi table,
mapping the entire disk.

the refit sourceforge project soft,
does not recognizes the gpt freebsd-boot.
and i cannot find how to boot from the internal drive.

i hope i am sufficiently clear?

of course, i can boot at this time from an external FreeBSD drive with 
a mbr and a label; this works.

Is it a solution to solve this problem other booting from an external
drive/Usb keyflash card?

Thanks a lot for your time and reply.

Raoul
rmgls<free.fr