[oracio]

It is a part of the "Advanced Render" module. If you dont have the extended version of Cinema 4D or bought the module you won't have this feature...
I have the same problem

[Tyrone Marshall]

Updated for 1.5.

The custom MXM is a wetclay MXM created in the 1.1/1.0 days.

As a side note, I run both a full installation of C4D R10 and the demo version of C4D R10 at the same time. I test these situations in both as an independent testing bed to look for problems. This test below was run from both versions using the same plugin that is available to the public. The result is the same.

Image notes: the MXCL render was only added on top of the Cinema 4D screen shot in photoshop as an image composite to conserve file space. I am using the same version of public release version of Cinemaxwell and having the MXCL preview in the plugin is not a new feature nor is it any indication of a future feature. Although that would be very interesting.