At the moment you can only automatically do it through the HH version of the forum:

http://www.headheritage.co.uk/headtohead/tma/

by using the reply 'with quote' option

You can manually do it in the TMA version of the forum by placing text between quote and /quote, both in square brackets. (If that doesn't make sense then pop over to the other forum and just click the 'with quote' link on a post and see what I mean.)

Thanks

TMA Ed