LAG between EX2300 and cisco VSS not coming up

Hi all,

i am not sure if what am trying achieve is possible, i need some  guidance.

We have 3 ex2300 switches in 3 sites , the switches are runnign RSTP.

on every site there are 2 Cisco switches forming VSS. from these two cisco switches there are two links connecting to the EX2300 and every VSS is requred to form LAG with the EX2300. 

we have set up the LAG but the AE interface is not coming up. checking the LACT statistics, i can only TX packets and no RX. 

we have tried with and wothout LACP. when LACP is enabled, we tried both ACTIVE/ACTIVE and active/passive  but still AE inteface remains down on the juniper. the port channle interface on the cisco shows up. 

configs as below:

# show chassis
aggregated-devices {
    ethernet {
        device-count 2;
    }
}

# show interfaces ae0
aggregated-ether-options {
    lacp {
        active;
    }
}
unit 0 {
  family ethernet-switching {
        interface-mode trunk;
         vlan-members all;
    }
set interfaces xe-0/1/2 ether-options 802.3ad ae0
set interfaces xe-0/1/3 ether-options 802.3ad ae0

set protocols rstp interface ae0.0

Regards

Lish