RESOLUTION
This is controlled by allow-axfr-ips variable in PowerDNS configuration file, so you may modify setting allow-axfr-ips in /etc/powerdns/pdns.conf configuration file inside HSPcomplete VE and restart PowerDNS:
# service pdns restart allow-axfr-ips=...
Only these IP addresses or netmasks will be able to perform
AXFR transfers. Thus be sure you setup all IP addresses of your nameservers. Keywords: AXFR,IXFR,PowerDNS