I found a possible solution you could try.
Well, it seems like something can be installed on there, but I'm not sure if it would blend in with every page background. Another thing I was looking at was using ShareLatex.com and putting a background on there similar to the target forum and then taking snapshots of that using a free tool and then uploading those to posts. But that's the difficult way to do it.Do you mean MathJax?
Jason is a paid poster on my forum. Has been doing a great job and I highly recommend him. Furthermore, you can always review his content here on FP.I might be interested if you could provide a test post.