low performance in projective decal in PLSM

Hello,
I have followed the post in http://www.ogre3d.org/phpBB2addons/viewtopic.php?t=498 and use getoption to retrieve the material name of the plsm. However, when i use the selection decal(frustum) in my application, it cause a big resource consumption such that 25fps out of 75fps are used. And when Initialize one more selection decal(frustum), it used up 25fps one more time. I have found no problem in selection decal(frustum) on other material, but a problem on PLSM landscape material.Can it be solve?
Thank You

Projective decal probably renders the entire terrain page that uses that material again for another pass. This is going to slow things down, especially if you have a slower 3d card, but regardless it's like rendering the terrain again with alpha blending enabled, which is slow.