Has anyone tried running an IPSEC LAN to LAN VPN between two draytek 2820s or a 3200 and a 2820 running over the Sharedband bonded ADSL service and got it to work with out packet losses making it unusable.

Sharedband have advise setting of MTU, MRU and MSS, but the poor/confusing and inaccurate documentation available for Draytek routers makes it hard to work out what these values are for the WAN port and the VPN.

Through telenet the following commands are available:

wan mut
wan mtu2
vpn mss

the one listed in a tutorial "wan ppp_mss" does not exist!

Can some one advise on the above please and possible settings to avoid dropouts.