Attached you will find an image that shows a solution that one of our other customers came up with and was able to implement, and they have not reported any issues. You may wish to try a similar setup.
Some items to note, however, is that the material you use will need to be RF transparent (ie: nylon or plastic) to minimize the effect on the antenna performance. We are also unable to support any modifications done directly to the antenna enclosure.
Regardless of the materials and method you use, we strongly recommend you test your setup to ensure that any negative effects on antenna performance are minimal.