Hi, Kim.

I'm not following the case closely, but I think I can still answer your question. If the judge has decided that evidence about Stacy being missing is inadmissible (and it sounds like he has), then he would tell the jury either (1) that the information they requested cannot, for legal reasons, be revealed, or (2) simply that Stacy is unavailable to testify in person.
Keep in mind that the judge is constitutionally required to be "defense-sided." The defense is the only side with any constitutional rights at all in a criminal case. Any other rights, rules, etc. have to take a back seat to the rights of the defense, because they are based on law that is "trumped" by the US Constitution.