Hi Husni !
In the origional script the mistake, as pointed out, was mentioning logical interface instead of physical one.
In the next script, you are setting next-hop to a Multi-Access interface (fe), which inside the script means like:
set routing-option static route 0.0.0.0/0 next-hop fe-0/0/0
This will not work unless the neighboring router does proxy-arp for the traffic from this router
Solution is to use the origional script with "st0" and "st1" as next-hops (no proxy-arp needed as tunnels are point-to-point entities) OR use the next script but explicilty modify the two scripts setting next-hop to IP address of neiboring router.
Regards, Rashid.