It works in my wordpress blog posts but it doesn't work when I insert the wordpress short code like this one into a SP post:

[slideshare id=49844177&doc=impervainsidelookatasophisticatedmulti-vectorddosattack-150625180605-lva1-app6891]

You need to add any short-codes you want to allow in forum posts to the forum admin > options > content settings panel. Enter the name of the short-code in question.

Thanks for your prompt reply YellowSwordfish....

I have a final question, in which format should I add the allowed shortcodes?

[slideshare id=49844177&doc=impervainsidelookatasophisticatedmulti-vectorddosattack-150625180605-lva1-app6891]

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???

Thanks! I already found it, it is without the brackets! 

slideshare

yes, the just the shortcode name without brackets or args...