accessing tcl variables within R and tcl

Dear R users,

I have some troubles with dealing with tclObj objects. I try to explain
it with a toy example:

Say I define the following tcl procedure which just prints out each list
element

library(tcltk)
.Tcl('proc test {myList} {
? ?foreach i $myList {
? ? ?puts stdout ?$i
? ?}
}')

and I call it with:

tcl('test',letters[1:5]) ? ?# Works as expected

Now say I define a tcl variable first:

a <- tclVar("")
tclObj(a) <- as.tclObj(letters[1:5])

tcl('set',a) ?# output list

However

tcl('test',a) # does not work as expected, returns the variable name

Why not? In fact, how do get the name of the "a" list in tcl (something
like RTcl...) so I could use it as follows

.Tcl('test $RTcl1') #works

Loops are much quicker in tcl than in R, hence I try to do some
computations in tcl and not via wrapper function in R. I therefore need
a way to easily access tcl variables from within R and tcl.