VLANS and Monitoring

We have a number of customers that have WAN links with us. In reality, these are VLAN links between a number of SM’s. We found that with the default management ID set as 1, the broadcast packets around the RF were propagating into the customers VLAN, and promptly moved away to issuing each customer a unique VLAN id with a corresponding management VLAN id (i.e. customer VLAN = 999, management vlan = 999). This resolved the issue, but is proving to be difficult to manage from a monitoring perspective, as our monitoring box cannot sit on all the numerous management VLANS. Anybody have any ideas on how to overcome this?