[R] Displaying Equations in Documentation

[Jarrett Byrnes]

I'm currently working on writing up some documentation for some of my  
code, but am having the darndest time coding in equations.  For  
example, the equation in the following:

\details{ Calculated the R Squared for observed endogenous variables  
in a structural equation model, as well as several other useful  
summary statistics about the error in thoe variables.

R Squared values are calculated as

\deqn{R^{2} = 1-\frac{estimated variance}{observed variance}}

Standardized error coefficients are then calculated as sqrt(1 - R^2).
}

While it shows normally using R CMD Rd2dvi, when I actually compile  
and load the package, displays as follows:

R^{2} = 1-frac{estimated variance}{observed variance}


I have also tried

\deqn{R^{2} = 1-\frac{{estimated variance}{observed variance}}}

and

\deqn{R^{2} = \frac{1-{estimated variance}{observed variance}}}

with the same result - Rd2dvi is happy, but the display is still wonky  
in practice.  I've also tried subbing in \eqn{R^{2}} in the rest of  
the text in a few places, but, again, it shows as R^{2}.  Is there  
something I'm missing about inserting equations into R documentation?

-Jarrett