[amibroker] Plotting hollow shape on scaled buys - how to ?

[gmorlosky]

I want to have a hollow shape on all buys after the first buy when 
scaling in, but since my second buy is designated by BUY = Buy + 
sigScaleIn etc., how do I plot the scaled in buys?

PlotShapes( Buy* shapeUpArrow , buycolor, 0);
// next line doesn't work..... 
PlotShapes( Buy* shapeHollowUpArrow, buyagaincolor, 0); 
PlotShapes( Sell* shapeDownArrow , sellcolor, 0);