Looking for "complex" cmdsynopsis example (for docbook-xsl)

Hello,

I'm using DocBook (both XML and SGML) to generate manual pages.
Most time I use docbook-xsl to generate nroff.  Now I have some
"complex" thing.  What I want to achieve is this:

shoecommand --pairofshoes <leftone> <rightone> [<buttons> ...]
shoecommand --pairofboots <right> <left> [<laces> ...]

OK, the example is stupid.  I have two ways to call the command.
With either option I have to required arguments and any number
of optional arguments, that can be repeated.  How do I have to
do this in DocBook?  And does docbook-xsl's nroff output provide
an output, where the user can see the difference between required
and optional arguments, and which arguments can be repeated?

Thanks in advance!

Cheers, WB