In order to compensate for https://bugs.documentfoundation.org/show_bug.cgi?id=98292 I tried to make wxMaxima put equations in several formats on the clipboard:
 - "math embedded in rtf"
 - MathML 
 - plain text
 - and bitmap.

Instead of the attached data libreoffice prefers the bitmap it can find on the clipboard and pastes the image instead of the equation into the document.

I am not completely sure if I got something wrong in the RTF export.
wxMaxima publishes the RTF data as "Rich Text Format" and as "text/richtext". It offers bitmaps as "image/bmp", "image/jpeg" and "image/png" (both at 75dpi and about 1kb long), the text as "text/plain" and the MathML data as the appropriate MimeType, as "MathML" and as "text/html" as it technically is a HTML5 element.

If I want it to import whole documents libreoffice uses the RTF code instead, though.

That is all I know about this problem.