wan multi ip l2tp-server

hello everyone
we have a application environment,the customer have multi ip on his wan,use RB750GL as a l2tp server,only one address on wan could use.
like this:

/ip address
add address=10.200.14.11/24 disabled=no interface=ether2-master-local network=\
    10.200.14.0
add address=10.200.14.12/24 disabled=no interface=ether2-master-local network=\
    10.200.14.0

/ip route
add disabled=no distance=1 dst-address=0.0.0.0/0 gateway=10.200.14.1 pref-src=10.200.14.12 scope=30 target-scope=10
add check-gateway=ping disabled=yes distance=1 dst-address=0.0.0.0/0 gateway=10.200.14.1 scope=30 target-scope=10

i set pref-src nothing only 10.200.14.11 can use as server address,if i set pref-src=10.200.14.12,only 10.200.14.12 can be use as server address
i also configur input and output

/ip firewall mangle
add action=mark-connection chain=input disabled=no dst-address=10.200.14.12 \
    new-connection-mark=1 passthrough=yes
add action=mark-routing chain=output connection-mark=1 disabled=no \
    new-routing-mark=1 passthrough=yes

/ip route
add disabled=no distance=1 dst-address=0.0.0.0/0 gateway=10.200.14.1 pref-src=10.200.14.12 scope=30 target-scope=10 routing-mark=1

can not solve

Known issue:
http://forum.mikrotik.com/t/known-issues-and-bugs-a-list/71473/43

MikroTik stated that it will be fixed in 6.13.