2 Code bank with Single SRAM

Hello,
If we create 2 Banks for our project, for using more than 64K program.

1.We wanted to common SRAM for both the banks. Please describe how we can control the SRAM with 2 banks program;

2.When we create 2 banks for program; after compile; our SRAM getting dubbeld

Details:
>> We are using 89C51X2BN, with External EP-Rom Winbond 27C010-70, SRAM: 62-256

>> earlier we are using Franklin 3.2; (Dos Based Compiler) and we created 2 different Hex Files(1 Main Program and 2 Print Program)
with this our product working perfectly,) the same we did in Keil PK51)
The system start working but when we use 2 part program; and same time used 1 Part program > system goes hang)

After seen the Code banking on keil site, we did required correction; result our SRAM dubbeld.

Please guide us.