configuration problem in RB 411AH

hi
I am new in networking between buildings

we have 1 RB411AH Router board
and 2 TP Link Wireless A P WA5110g setup are as follow


Building A has broadband Internet Connection and have 1 TP Link Wireless A P WA5110g on it

Building B has 1 RB411AH Router board

Bulding C has 1 TP Link Wireless A P WA5110g on it

These setup work fine from 2 year but when we replace RB411AH Router board with new one
I am not able to configure these thing

please help

Thanks in advance

s first check the os level if your level3 you can choose virtual ap to connect this two clients
. normally rb411ah is level 4 it should support ap mode

thanks jeraldvimal I am using ap-bridge mod and confusing in add ips for route