Seen on Glassfish ESB 2.1 on windows Vista:
PRODUCT_BUILD=20090429-0723
NETBEANS_BUILD=200904151427
NETBEANS_VERSION=6.5.1
SOA_BUILD=090429

1. Open a new IEP document in the IEP editor.
2. Add two operators that can be connected.

=> There is no way to add a connection without using a mouse. 

A common way to implement this would be to enable the following series of user actions:
1. Select an operator.
2. Shift-F10 to pop up a context menu on the operator.
3. Choose a menu item like "Add Connection".
=> A list of operators that can connect to the current operator is displayed.
4. User uses keys to navigate to the operator to be connected.
5. User chooses OK, which closes the dialog and creates the connection.