I finally got this to work just the way I wanted. I checked the result to see if it was an array ref, then formed a sub-table if it was:

#massage multi-values for formatting                             
if ( ref $encodedvalue eq 'ARRAY' )                              
{                                                                
                                                                
    my $listtable .= $cgi->start_table({-border=>0});           
                                                                
    for ( my $i=0; $i<scalar( @$encodedvalue) ; $i++ )          
    {                                                           
        $listtable .= $cgi->Tr({},                             
                    $cgi->th(@$encodedvalue[$i])            
                    );                                      
                                                               
    }                                                           
                                                                
    $listtable .= $cgi->end_table();                            
                                                                
    $data .= Tr({},                                             
                $cgi->td({-class=>'label'},                      
                         $attrHash->{ATTRNAME}),                 
                $cgi->td({-class=>'value'},                      
                         ($listtable || $cgi->p('&nbsp;'))));    
                                                                
}                                                                
                                                                
                                                                 
else {                                                           
    $data .= Tr({},                                              
                $cgi->td({-class=>'label'},                      
                         $attrHash->{ATTRNAME}),                 
                $cgi->td({-class=>'value'},                      
                         ($encodedvalue || $cgi->p('&nbsp;')))); 
                                                                 
}}
[download]