You mean to say that you need a dynamic request, media type and attachment?
For setting dynamic request -
https://community.smartbear.com/t5/SoapUI-NG/json-block-as-a-property-value/m-p/144532#M32717
For setting dynamic attachment -
There is a thread I was searching for this, could not find.
You can use test case level custom properties and use Property expansion for the directory and filename in the attachment part.
Similarly, use custom property for Content-type and use property expansion for the same.
Refer here to know more about Property Expansion
