Hi Shaan,
"""from 192.168.1.254 it should reach 192.168.4.254 as 192.168.2.2 and when 192.168.4.254 tries to reach 192.168.2.2 it should then NAT to 192.168.1.254 """
I understand you want source NAT when initiating the traffic from 192.168.1.254 it should reach 192.168.4.254 , AND destination NAT when 192.168.4.254 tries to reach 192.168.2.2 .
If you apply MIP on eth0/5 of ConnectorSSG then source NAT will not trigger correctly . Try applying the appropriate MIP on UntrustSSG(Eth0/0)
1: set interface "ethernet0/0" mip 192.168.2.2 host 192.168.1.254 netmask 255.255.255.255
2: Call MIP in appropriate security policy.
Thanks,
Vikas