the soft limit problem of a 6 DOF arm

Dear everyone:
Currently,I intend to control a 6 DOF robot with LinuxCNC and the kinematics is genserkins module.The limits of joints are described in the [AXIS] section in the ini file and the unit is degree.
While i run the LinuxCNC, i will see the soft limit which show by red-lines is just a cuboid. Obviously it is wrong and it is not the workspaces of the robot, then I find out that the soft limit is just using the limits of joints in the ini file without computing, for instance,when the MIN_LIMIT is -180 and the MAX_LIMIT is 180 which I set in the [AXIS] section in the ini file, then the limit of X axis in the AXIS user interface is just a range of -180 to 180.
Can anybody have a solution to this problem?
Thank you very much

thanks for replying,I understand your meaning.
It is right that the cuboid showing in the AXIS user interface do not affect the robot to work and the real workspace of robot is just what you said, a strange 6-dimensional shape.
what I doubt is that whether the LinuxCNC have a protective action when the robot is really on the actual joint limit if I don't use the Joints_Axes branch of LinuxCNC.
thank you very much

Sorry for disturbing you again.
I just deal with that as you say. I choose the joints_axes4 branch,everything is ready,but when I run LinuxCNC,there are some issues occuring:
insmod : error inserting '/usr/realtime/module/rtai_math.ko' :-1 unknown symbol in module.
then I run 'dmesg' in the terminal, it shows:
rtai_math ：unknown symbol sqrt(error0)
rtai_math ：unknown symbol log(error0)
rtai_math ：unknown symbol cosh(error0)
rtai_math ：unknown symbol fmod(error0)
rtai_math ：unknown symbol sinh(error0)
rtai_math ：unknown symbol atan2(error0)
rtai_math ：unknown symbol pow(error0)
rtai_math ：unknown symbol asin(error0)
rtai_math ：unknown symbol acos(error0) .....
Kernel version is 3.4.6 rtai.system version is Ubuntu 12.04. the other pc, the kernel version is just 3.4-9-rtai-686-pae.system version is debian 7.9 wheezy
Is the version of branch not suitable? Which one is better?
Thank you again

I choose the joints_axes4 branch,everything is ready,but when I run

The last commit on joints_axes4 was over two years ago: 9d13abe 2013-12-21

The current branch is joints_axes13

Important updating notes are maintained in the LinuxCNC getting-started guide in the
updating-LinuxCNC section. The link to html docs for scratch branches like joints_axesNN
changes after every new set of commits. The scratch build docs can be found at:
buildbot.linuxcnc.org/doc/

For example, from a recent build, the html docs start at:
buildbot.linuxcnc.org/doc/scratch/v2.8.0...-axes13~12df108/html

The updating-linuxcnc section is:
buildbot.linuxcnc.org/doc/scratch/v2.8.0...dating-linuxcnc.html