Help: DNS/GTM as slave of another DNS/GTM

Hi,

I am stuck with one configuration. Right now i have two DC, HQ and DR, with one GTM on every DC. Both of them has been configured to work with GSLB, and they sync their conf. (but not their zones) Today i imported one domain zone into DNS HQ and now it behaves as master. I now want to configure the second one as slave of the firts one. I am using the zonerunner but so far no luck.

Any help? This is the example of slave DNS