Often times the file you are currently editing is only a fragment being \input'ed into a master tex file. In such cases you will need to do create a dummy file in the directory containing the current file. This dummy file is of the form: <mainfilename>.latexmain
As an example, suppose you have the following setup:
% file: main.tex \documentclass{report} \begin{document} \input{chapter1.tex} \end{document}
In other words, even when you are editing chapter1.tex, you want to compile main.tex. In this situation, create a file called main.tex.latexmain in the directory containing chapter1.tex (and main.tex). After doing this, when you press \ll while editing chapter1.tex, then Latex-Suite will compile main.tex instead.
Here main.tex.latexmain is (obviously) a different file from main.tex itself. main.tex need not be renamed. The contents of main.tex.latexmain are not used. This ofcourse restricts each directory to have a single master file.