Live Connect call Java 2 JS for CA signed applet should be allowed. But with latest 7u45#224, "Java to JS" calls don't work as expected.
Steps to reproduce:
    1) Install latest jre7u45#224
    2) Enable trace and java console from JCP
    3) Disable OCSP/CRL check from JCP: Open JCP->Advanced->"Perform certificate revocation checks on: ": Check "Do not check (not recommended)"
    4) Load applets :
http://sqeweb.us.oracle.com/net/sqenfs-1/export1/comp/jsn/users/crystal/DO_NOT_REMOVE_ME/jrebug/CASignedLiveConnect/html/testHigh_Java2JS.html
    5) There will be a Java to JS call in above CA signed applet
    6) Accept the CA-Signed security dialog
    7) If no mixed code dialog shows up and an exception "netscape.javascript.JSException: Unspecified error invoking method or accessing property "fromJava"" shown in java console, this issue is reproduced.

Source code: http://sqeweb.us.oracle.com/net/sqenfs-1/export1/comp/jsn/users/crystal/DO_NOT_REMOVE_ME/jrebug/CASignedLiveConnect/src/HelloWorldApplet.java

It works fine with 7u40:
    1) Install latest 7u40
    2) Enable trace and java console from JCP
    3) Disable OCSP/CRL check from JCP: Open JCP->Advanced->"Perform certificate revocation checks on: ": Check "Do not check (not recommended)"
    4) Load applets :
http://sqeweb.us.oracle.com/net/sqenfs-1/export1/comp/jsn/users/crystal/DO_NOT_REMOVE_ME/jrebug/CASignedLiveConnect/html/testHigh_Java2JS.html
    5) There will be a Java 2 JS call in above applet
    6) Accept the CA-Signed security dialog
    7) Click "Don't block" for mixed code dialog.
    8) You will see ">>>Result is true Cause: Java 2 JS call successed" in java console