my $ua = LWP::UserAgent->new;

my $content = { example => "content", name => "me" }

my $request = Net::OAuth->request("protected resource")->new(
       consumer_key => <key>,
       consumer_secret => <secret>,
       request_url => 'https://someplace.whatever',
       request_method => 'POST',
       signature_method => 'HMAC-SHA1',
       timestamp => time(),
       nonce => 'kllo9940pd9333jh',
       token => <token>,
       token_secret => <secret>,
       extra_params => { foo => 'bar', %{$content} }
);

$request->sign;

my $res = $ua->post(
       $request->to_url,
       Content_Type => 'form-data',
       Content => $request->to_post_body,
);