First, you'd get a much faster response on questions like this in the TDR Website/Roundtable forum - the main purpose of that forum is to answer questions as to the use of the website. You'd get an even faster answer if you look in the TDR Website/Roundtable FAQ forum that is inside of that forum - there is a post about exactly this situation. We answer this question every few weeks.
The truck profile does not show up in posts. Your truck profile does show your 2007 truck. What you are trying to edit is your signature - that's what appears at the bottom of your posts. The signature is limited in length and content. The truck profile is unlimited in length - for you to see someones truck profile you click on their username and then click on "view public profile". So if you edit your signature (same place as you when to edit the truck profile - the user control panel) you'll get done what your trying to accomplish.