Group and Target of the Business System does not appear in SAP PI 7.5.

Dear Experts,

In the business system, i would like to configure the group and target in the development environment. I've done the steps below but when i tried to assign the group and target, there is nothing appearing the drop down list. Please share some light with me. Thanks in advance.

1. Create the group in business system page and choose the integration server. I've created this in both Dev and QA environment.
2. Click on the "Add/Change Target" at the transport tab of the business system but i could not find any option for me to choose.

Regards,
Shawn