Backreferences on substitution?

Hi all,

it seems the archives are unreachable, so I will fire this question
without having first searched for an existing answer... please bear with
newbie ignorance ;)

Is it possible to specify backreferences on substitution patterns? The
probl is: I would like to get rid of some tags but leave their content
untouched. This pattern correctly catches data on the form
<tag ...>data</tag>:

<([:alpha:]+)[^>]*>([^<]*)</\1>

However, if I want to use it on a text where it appears multiple times
with RE.subst(), how do I pass a backreference to the second capture to
the 'substitution' parameter? For example, this text

<tag1>this text</tag1> should <tag2>remain untouched</tag2>

should become

this text should remain untouched

Any clues? What am I missing?

TIA

Andre

-- 
Andre Oliveira da Costa