If there are not too many of those messages, you can always work around the problem - select the message you want to print, press the "berry" key and select "Forward as -> E-mail". Then you can send an e-mail containing the actual SMS with timestamp to anyone. HTH
edit: Of course, than you can print that from any computer that receive that e-mail (if that needed saying)
There are BB apps that forward your texts to your email. You can then print the important ones from your email. TextBasket (http://highglacier.com) sends groups of texts in one email - most of them send each text as it comes and waste a lot of bandwidth.