finding approach chart URLs

I know I can find them at various web sites, please don't bother to
respond to tell me about them.

Here's what I'd like: given an airport identifier, say "KLHZ", I'd like
an programmatic, algorithmic way or a table lookup to find all the NACO
approach chart URLs, like:

http://204.108.4.16/d-tpp/0704/09131IL5.PDF
http://204.108.4.16/d-tpp/0704/09131R5.PDF
http://204.108.4.16/d-tpp/0704/09131R23.PDF
http://204.108.4.16/d-tpp/0704/09131VDA.PDF
http://204.108.4.16/d-tpp/0704/SE2ALT.PDF

I can see that the file names have some logic to them, like IL for ILS,
R for RNAV, etc, and the runway numbers are part of the name. If I knew
beforehand that LHZ had an ILS approach to runway 5, I might even be
able to generate the name for that chart, but I'd like to be able to
start from just the airport identifier and generate the list of approach
chart URLs.

I'm missing the information that relates a given airport to its list of
approach charts.

Anyone?

Thanks.

Dave