Hello Sameer,
We added an updated document to the the survey Codeplex site that explains how to add new AnswerTypes to the Survey Project tool.
You can find it at the Documentation section:
http://survey.codeplex.com/documentation
Download:
Adding New AnswerTypes
The second part of your question can be handled in different ways:
- you can make use of the help text option that is available when you create a new question (help text + click show helptext)
- you can make use of scripting (javascript/ ajax or jquery) and add script through the html/text editor when creating questions
- to use and reference scripts already used by the SP tool check the Scripts directory in the SurveyWAP rootdirectory
Hope this will help to find a solution.