MS Word 2007 ignores the MathML color attributes when pasting MathMML into it.

For example, pasting the following two gives the same results in MS Word 2007. Does anyone happen to know if it is the limitation of the MS Word equation editor or I am missing something here? In a MathML compliant web browser (or any browser +MathJax) the second example below displays the expression under radical sign with a yellow background.

Example 1 (No MathML color):

<math xmlns="http://www.w3.org/1998/Math/MathML"><msqrt><mrow><msup><mi>a</mi><mn>2</mn></msup><mo>+</mo><mn>1</mn></mrow></msqrt></math>

Example 2 (mathbackground attribute used)

<math xmlns="http://www.w3.org/1998/Math/MathML" display="block"><msqrt><mrow><mstyle mathbackground='yellow'><msup><mi>a</mi><mn>2</mn></msup><mo>+</mo><mn>1</mn></mstyle></mrow></msqrt></math>

Thanks..Saf