A. Crispus flower spike

My A. crispus has put up three flower spikes over the last two months.  
Although the plant seems healthy, I haven't had any seeds develop.  The 
spike reaches the top of the water, then grows along the glass looking 
for a place to get emersed, I assume.  The first spike, I let it stay 
under the glass, and although it put out the white tip and looked like it 
was trying to put out pollen, nothing I would call flowers ever 
developed.  After a couple of weeks it died (the flower spike).  The 
second one I let get out (my top covers the top of the tank pretty well) 
with similar results.  The third is going now, and looks just like the first.

How do I get seeds?  Does the flower spike need to be in the light?  I 
can let it stick out above the water, but then it will be above the 
light, as well.  Should I lower the water and let the spike become 
emersed beneath the glass?  Also, I am having some trouble figuring out 
when to pollinate the flowers with a small paintbrush.  The end stage for 
all of my flower spikes has been when the white tip develops a regular 
pattern of rough places, which I think want to be flowers.  The rough 
spots are about 2mm across and spaced at about 6mm, I would guess.

Thanks for any help.