You can check in a limited way in Milkshape itself. There's some instructions here: http://www.modthesims2.com/showthread.php?t=288985

It helps if you import a body mesh too so you can see how your hair will look against a body. I like using it to test smooth animation when the head turns, tilts, etc... it's not foolproof and it won't show you differences that the game imposes - i.e. the way one hair mesh's animation bones reacts differently than another, but it is a good starting point and will cut down on the amount of in-game testing you have to do.

Thanks! I found a row, the one before the last of the back, has got a problem with the bones! I'll try to correct it later, I have to study... Next week is full of exams... But I'll be on summer after friday *_____*

Edit:

HP... where can I found a tutorial for make a mesh for all ages?? I only know how to do for young, adult and elder because is the same mesh, but for pf, cf and tf...

sorry 4 the double post, but, can anyone answer me? Many peopled asked to me to make the hair 4 all ages, but I tried it, and pf, cf and tf have errors, the mesh is more up than usual, or at the bottom...

Dr Pixel has written instructions regarding different age hair meshes. It's the second post down in the tutorial.

http://www.modthesims2.com/showthread.php?t=139819

Thanks! but one question. I have to re-made the bones, no? =(

If you use that method, yes. However, I prefer a slightly different method...

1. Import a GMDC from the age you're converting to. That is, if you're converting to teen, import a teen GMDC. This gives you the right skeleton.
2. Import the example bodies/faces from here. You want the first ones, the Dr. Pixel ones.
3. Import your existing GMDC from the adult age that you have done. This will keep your bone assignments.
4. Use the scalps from the example bodies/faces as your "hair" group. I -always- use the regular scalp as my "hair" group even on my adult bodies so I can do age conversions like this easily without any trouble. Scale and move your other existing groups you're converting to fit the bodies/faces.
5. Make sure to assign the "hair" group (the scalp) as it will be the only thing unassigned. Make sure to test your animations in Milkshape and then in-game to make sure they converted okay and look good on the other body. Sometimes you may have to adjust slightly but it's better than starting over.
6. You will, of course, have to make sure that your hair recolour has the right number of groups for the other ages too, and that your groups are in the right order. Cloning from melodie9's hairs (available here at MTS2) is a good idea if you need more groups, or there's instructions on adding more here.

So...
I open my adult mesh, I add a obj "cf body-face" that I made before.
I scale the hairalphas minus the hair(i delete). when it's okay I delete the obj group and export
Is this?
I used for make the hair:
pfHairMob (hairalpha 3 and 5)
cfhairfuzzylong (h.a. 3 5 7 9 11 13 15 17) but I only use 9 and 11
tf/afhairlong (h.a. 3 5 7 9 11 13 15 17) I only use 9 and 11
(sorry, many things that you say I don't understand, so I translate with google and it's terrible for understand)
Edit:
I succedeed! I tested it in the bodyshop, all ages look greay, only one error in teen, the f_hair is wrong, but tomorrow I'll repair it, thanks so muuuch!

Hi again!
I have the hair, but not for all ages

(Próximamente=Coming soon)
I tried to correct the children and teen ages but I didn't succedeed.

I don't know what I have to do. I think for child the problem is the hairalpha(number) probably I have put it bad. But teen, I tested it in milkshape, and all is okay.
The sims are the same from adult to the other ages, and the recolors, in child, the recolor is so dark and the inside layers are inbisible...
I''m going to make you crazy jajajajajaja
(edit: child's problem corrected!)

At the end, I fihished it, (4 days ago) and in this 4 days, I made a new hair, I have just uploaded it =) now, wait for the validation xD