SSG20 site to site dynamic vpn dont work issue

Dear All,

i tired all senarios to make two SSG 20 to have site to site vpn using dynmaic ip address in site B, not no worthy. It works when both sites have fixed ip address but when Site B has dynamic ip address it doesnt work.

Site A public ip address 82.114.183.222 and its lan is 192.168.2.0/24.

Site B has dynamic public ip address and its lan is 192.168.4.0/24.

What is the wrong in the attached configuration???

Could you please share the best worked and guarnted configuration example?? i did exactly using juniper resources but doesnt work.!!!?

thanks to all.