Mivoice 400, 69xx SIP phones, DHCP, voice VLAN and Fortinet

[gurei]

Hi all.
We have MIVO400 SMBC which was working fine with 69xx SIP phones on a network that had PCs and phones on the same subnet. Recently we separated subnets and created a second one for the phones and a voice VLAN.
We are using Cisco switches and configured the voice VLAN on all access switchports. The phones must get DHCP from the SMBC. PCs connect to the back of the phones and get DHCP from Fortinet Firewall. When connected to the network the phones are not getting the voice VLAN ID and fail to get IP addresses (If I test with a phone on MINET it gets the voice VLAN ID). They get stuck on "20% DHCP: Waiting for IP". What configuration must I do on the Fortinet to enable the phones to get the voice VLAN ID and make the request DHCP from SMBC?
Please advise.

[crazyscout]

You have to make sure that wherever the SMBC connects to your network stack that the VLAN is tagged between SMBC and the Switches so that it can provide DHCP when the phones broadcast requesting one. As long as the phones voice vlan is the same VLAN the SMBC is tagged on then the DHCP request which is a broadcast from the devices will reach the SMBC and it should assign an IP address to the phones.