[Yasushi Kono]

you have to alter the global properties. Launch GuiDBedit and look for the parameter :ipsec.copy_TOS_to_inner and :ipsec.copy_TOS_t_outer.

You should set both parameters to true. That' s it.
Of course, you could modify these settings with dbedit. You should be familiar with this tool.

Kind regards,
Yasushi