That invitation is very easy, its just one picture with writing. That is too much info to put in this email to create that.
If you want that exact firework, what you can do is print out that picture , trace it, and bring back in to any vector editing program.
If you want that same feel, but want to use clip art , just "insert clip art"
But then you have printing issues and so forth....alot of info.
Or you can just have someone do this for you.
I just had a party and got personalized invitations from this place here
http://stores.ebay.com/Big-Boo-Stationery_W0QQsspagenameZMEQ3aFQ3aSTQQtZkm&refid=store
They were good price and quality and very accommodating. I actually liked there designs, but wanted something specific, so I just emailed them and told them what I wanted and they created something for us. Actually did a couple of different versions and they did the size that we wanted. So if you send them that pic then can recreate for you and print out so you get what you want, affordable price and dont have to worry about printing and all that other stuff