EPM x Grandstream

We use EPM to provisioning our peers and it is excellent, but I am getting an issue with Grandstream GXP 1625. It is not getting the right information about my TIMEZONE.

In EPM, my timezone is okay (I have Yealink using that info and they are running fine).

These are the keys that are related to timezone:

P30 (NTP Server)
P64 BRST+3BRDT+2,M10.3.0,M2.3.0

There is P246. It should be a customized timezone.

I tried to use P64 with “auto” or “customized” (and fill P246)… tried P64 empty… only P246 filled. Nothing works… The Grandstream comes with +6 of timezone (we use -3). Here are my questions:

  1. Anyone has the light?
  2. Why EPM fill BRST+3 (plus ?!)… We are (- minus) GMT -3
  3. When I try to contact Grandstream support, they insist that I should use XML provisioniong files. Will EPM stops to work with Grandstream?