encrypted email in iOS / exchange domain

hi,

i'm using encrypted email time to time on my PC using outlook 2012 and a smartcard.... fine

my iphone is set up with this exchange account... fine

I was not able to read encryted email (normal!) untill i've exported my certificate to the iphone.... good !

but now:

when the certificate is active: i cannot distinguish encrypted email from non-encrypted ones; and if I forward these encrypte email, there are not crypted anymore...

so if I activate s/mime in the exchange account on ios, then all my email all encrypted.... 😟

how can I toggle easily between encrypted and encrypted ? as I can do it easily on my PC outool ???

I don't beleive it' s not possible on iOS 😉

thanks

cyril