[asterisk-users] SIP MWI Problem in 1.4 and 1.6

[MFH]

I've been having a problem with Asterisk MWI notification on my SIP 
phones since going to version 1.4 a long time ago.  Since going to this 
version, I have needed to go into chan_sip.c and do the following:

/*! \brief Check whether peer needs a new MWI notification check */
static int does_peer_need_mwi(struct sip_peer *peer)
{
   time_t t = time(NULL);

/* COMMENT OUT THIS CODE
   if (ast_test_flag(&peer->flags[1], SIP_PAGE2_SUBSCRIBEMWIONLY) &&
   !peer->mwipvt) {
      peer->lastmsgcheck = t;
      return FALSE;
   }
*/

   if (!ast_strlen_zero(peer->mailbox) && (t - peer->lastmsgcheck) > 
global_mwitime)
      return TRUE;

   return FALSE;
}

After commenting out the section noted above then MWI works fine on all 
phones.  Now, I have moved to 1.6 and am having the same problem except 
this function no longer exists.  Has anyone had a similar problem and if 
so, how did you fix it in your config files assuming it's some setting 
in one of them?  Does anyone know why this flag test is not working?  
Also, if someone knows how I can patch 1.6 to fix this that would be 
helpful also.  I have the corresponding mailboxes set in my sip.conf 
contexts as so:

[sipiura1]
...
mailbox=55 at default,66 at default,99 at default
subscribemwi=yes
...