The causative structure is really for when you have paid/asked for something to be done, e.g. the gardening.
I had those horrible weeds dug up.
The above example shows the form have + object + past participle.
In the case you describe, you cannot make the listeners enjoy the speech, so you can't use the causative form above. You can of course be the cause of their happiness/enjoyment if your speech is good, which is why we have to say more directly:
I hope you will enjoy this lesson/lecture.
So if you can't say enjoy, what can you say? Well, since it must be something that you can make happen, let's try "laugh":
I hope I will have you laughing by the end of this talk.
This verb can be used, since it is you who is directly provoking the reaction (of laughing).
So have + somebody + verb + -ing is the structure we can use for a result that you create:
I had them eating out of the palm of my hand.
Have + somebody + infinitive is the structure used when we want to talk about the person who did something that we paid/asked them to do:
I had the gardener dig up those horrible weeds.