[tipauni-help] How to set font just for tipauni?

["??????" <syvshc@xxxxxxxxxxx>]

Dear sir/madam:

Thanks for the tipauni package. It makes me typing tipa symbols in my unicode document. 

However I have a template which I have to type tipa on it. I can't change the template font "TeX Gyre Termes".

But this font doesn't contain the glyph that tipauni needs, like:

\documentclass{article}

\usepackage{fontspec}

\setmainfont{TeX Gyre Termes}

% \setmainfont{CMU Serif}

\usepackage[preservefont]{tipauni}

\begin{document}

  \fbox{\textrtaild}, \fbox{\textipa{4}}

\end{document}

it will produce 

so how can I display tipa glyphs without changing the main font? Thanks.