Isnt it annoying when you want to do long animations , want to render in 5 minutes , not picky about detail , but crud! , The insides of hair doesnt show up in preview mode , so if your looking side on at hair at maybe the bangs that stick out , sometimes they will be invisible . Well heres how to get the inside of hair  to show in Preview mode.

Step 1) Load Hair
Step 2) Do the morphs and colours you want
Step 3) Use group tool to reverse normals on this hair. ( should look wierd now)
Step 4) Duplicate this hair
Step 5) On the duplicate , reverse normals again.
Step 6) Conform both hairs to your character.
Step 7) Make sure to preview render with Enhanced multilayer Transperency. (poser7)

• PS - reason for first making reverse normals then re-reversing is to get round a colour bug in poser.

Now you should have a preview mode that has the insides of hair shown!!!

Great advice.  Will have to bookmark this when I get home.  Thanks.

I get a bug whereby if I have duplicated the hairs , and I reverse one. The other hair becomes a wierd colour on one side of the hair.

Often blonde goes a bit orange.

However , If I reverse the hair first , then duplicate it. Then I re-reverse the hair. The wierd  colour occurs but on the other hair but on the reverse textures , so you dont notice it .

Quote -
Step 4) Duplicate this hair

Poser 6 doesn't have the option to "duplicate".

For users of Poser 6 and lower, if they are using a hair prop, they would have to reparent the first hair to the universe and then load the second hair which would be parented to the head, and then reverse normals on both hair.  I suppose after that you could parent the first hair to the second hair so that they both move together if you need them to.