lower case Greek letters

Hello,

I am having difficulties creating lower case Greek letters.

For example

plot(0,0, type = "n")

text(-0.5,1, expression(beta) )
text( 0.5,1, expression(alpha) )

produce the upper case letters B and A.

Running 

demo("plotmath") 
In the Symbolic Names 

Alpha - Omega   ! 7
alpha - omega   Capital greek letters

so I suspect it may have something to do with my system, but
I am at a loss as to what.  Any suggestions as to what to check
would be appreciated.

I am running R version 2.1.0 on Debian Linux - version sarge.

Thanks,

Matt

Matt Pocernich
Research Applications Laboratory
(303) 497-8312