So, I’ll try to explain the problem. We have a RB450G which is used with 2 internet connections - ADSL and a PPPoE connection. We want to make a PPTP connection to the company server ( Windows 2003). The main connection to internet is PPPoE and when it is down, I have set destination 3 to the ADSL connection, so the net start through the ADSL. There is no problem with the PPTP connection to our server when it is made trough the ADSL internet. But when the PPPoE “returns back” the PPTP client can’t connect. The only way to connect is to delete the pptp client and to create it again with another name and connects almost instantly. The RB is with 3.23 firmware. I couldn’t find a decision for this problem. 
Thanks in advance for any help!
P.S. Another strange problem. When is connected through PPPoE a site which ping replies can’t be opened, but when I change the router with a linksys the site opens without problems on the PPPoE connection. The strange think is that the problem is missing when use ADSL. I had to make a route for this site to be connected through the ADSL. The firewall - nat table is only with srcnat masquerade.