450i SM connections

Do you think we can connect two cameras to 450i subscriber module ! 

one camera on the aux port and the other on the main port 

attached drawing for more clarification 

Yes, you can! You'll need to make sure that whatever you're driving off of the AUX port does not use more then 30w however. From the spec sheet:

SM Power Consumption 15 W typical, 25 W max, 55 W max with Aux port PoE out enabled

Input Voltage 48-59 V DC, 802.3at compliant