Connecting two asterisks using SIP - goes to default context

Hi,

I have two asterisk machines connected using SIP.
When I call from box A to box B it works fine but, it always starts
in context default.
I tried to configure it to start at context myctx, but it does not work
Any idea how can I make it go to other context?

Info:
I call from Asterisk A to Asterisk B using SIP>

Asterisk A - sip.conf:

[xroute]
host=xxx.yyy.zzz.www
dtmfmode=rfc2833
type=friend
context=myctx
;insecure=very
nat=no
disallow=all
allow=ulaw
allow=alaw
allow=g726

Asterisk B - sip.conf:
[sip_proxy]
type=peer
context=myctx
host=XXX.YYY.ZZZ.WWW

The dial command in Asterisk A is:
exten => s,n,Dial(SIP/${DST}@xroute)

Thanks.

Could it be because you defined A only as peer?