If you go into "Add Reply" not "Fast Reply" at the bottom of the page, it takes you to a new window. There is a browse button below where you enter the text that enables you to choose the file, then click the "Upload" button next to it. Repeat for each pic.
Alternatively, I use photobucket.com which is free hosting for pics and you can copy the links over into the thread on here for people to look at.
The other guy who I was up the top of the tower with (apart from Dan), do you have any pics available yet as they would be superb from that height, sorry forgotten your name!