[henricos]

Code:

import xbmcvfs
import urllib

path = urllib.quote_plus('/home/akva/sample.rar')

(dirs, files) = xbmcvfs.listdir('archive://%s' % (path))
src = 'archive://' + path + '/' + files[0]
dest = '/tmp/' + files[0]
print('copy %s to %s' %(src, dest))
xbmcvfs.copy(src, dest)

works just fine for me. 

Thanks!
I see now that I was missing the RAR filename in the src parameter

But it didn't worked with the 'archive' protocol.
Had to change to rar or zip based on the file extension

But this is not a problem for my scenario

Thanks again!