Graphviz: how to rotate a node (or a subgraph)?

I am trying to have a node (or a subgraph, enclosing a node - whichever is possible/easier) rotated, like shown in this image:

(Note that it doesn't matter to me if the "B" label is rotated - only that the 'verti-*' texts in the record [or rather, the whole record node] are rotated as shown)

 

However, the closest I can to that, is the following dot code:

digraph graphname {
    node [fontname=Monospace, fontsize=14]; 
    subgraph clusterMasterBox {
        node [shape=record];
        l1 [label = "{ horiz-1 \r| \
 horiz-2 \r| \
 horiz-3 \r| \
 horiz-4 \r} \
"];
        subgraph clusterSubRotateBox {
            rotate=90;
            node [shape=record,rotate=90];
            l2 [label = "{ verti-1 \r| \
 verti-2 \r| \
 verti-3 \r| \
 verti-4 \r} \
"];     
            label="B";
        }
    label="A"
    }
}

The only reason I have the subgraph clusterSubRotateBox there (and the only reason why it is nested inside the clusterMasterBox), is because I hoped I could assign rotation to it, but apparently I cannot - as the above code generates this image:

So my question is - is there a way to rotate a record node; if not on its own, then maybe as a part of subgraph (or a different kind of 'object')?

Thanks in advance for any suggestions,
Cheers!

there should be a "rotation" attribute on the graph object (see http://www.graphviz.org/doc/info/attrs.html#drotation) but it didn't do anything in my test. and, it would only apply to the whole graph (not cluster/subgraph) according to the docs. i guess you'd first render the subgraph to postscript and then include it in the final graph as a custom shape for a single placeholder node. if you can't get "rotation" to do its thing, surely postscript has a simple way to apply a transform (rotation in this case), probably as simple as prefixing the generated code with some coordinates definition. sorry for the handwaving but i don't have time to try it now.