I think you have to do this in two steps. First you buy at least $2000 of TSM so that you have at least $10,000 in TSM using the money from the money market fund. Since this is a purchase it would not be a taxable event. Then you can request that the Investor shares be converted to Admiral shares. Vanguard can do this and it would not be a taxable event since you are just changing classes of shares within the same fund. Vanguard would probably do this without asking, but, making the request speeds the process.
Edit: Well I see that I am late to the responce since several other have already made the suggestion and in fact the OP has figured it out for himself.