There are two ways to do this. You can either go to setup and then "Session" and use the "pull up" or "pull down" to try to align the audio with the video (a little or even a lot of guess work may be in order here). Pulling up or down the Video can help as well.

OR

If you want to convert without using "pull up" or "pull down" , under sample rate, choose 48k and click on the drop down box to the right so that you can select up/down "48.048". Now you can bounce the file to disk. When you import into ProToolsHD un-check "apply SRC" in the bottom left section of the import audio window and click done.

Important Note:
If this session has to work correctly on other people's computer's as well as yours then sending a test copy would be EXTREMELY wise once you have it lined up. The last thing you want is to get done with the whole session and have to start all over because it only works on your computer.