I'm probably misunderstanding your post, but you can place method calls on soap objects. At least, on my laptop :) Here's an object I have in a little script in my cgi-bin:

#!/usr/bin/perl
use SOAP::Transport::HTTP;

SOAP::Transport::HTTP::CGI->dispatch_to('Object')->handle;

package Object;

sub new {
    my $class = shift;
    $class = ref($class) || $class;   
    return bless { '_cache' => [] }, $class;
}

sub set {
    my ( $self, $arg ) = @_;
    $self->{'_field'} = $arg;
    push @{ $self->{'_cache'} }, $arg;
}

sub get { shift->{'_field'} }

sub all { shift->{'_cache' } }
[download]

Here's a simple client:

#!/usr/bin/perl
use strict;
use warnings;
use SOAP::Lite 
    +autodispatch => 
        uri   => 'http://www.perlmonks.org/Object',
        proxy => 'http://localhost/cgi-bin/soap.pl';

my $obj = Object->new();

for ( qw'So how is it possible that it stores and returns these? ???' 
+) {
    $obj->set( $_ );
    print $obj->get, "\n";
}
print join ' ', @{ $obj->all };
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And sure enough, it prints:

So
how
is
it
possible
that
it
stores
and
returns
these?
???
So how is it possible that it stores and returns these? ???
[download]

I'm not quite sure how SOAP::Lite does this - some sort of session? And not even under mod_perl or anything, frankly I don't quite get it...