sending data with SoapUI using MTOM

Question

Hi,

I'm using SoapUI to tranfer data on to an ARM target. I have to use MTOM when sending the data. I'm able to do this, where SoapUI (after setting the required flags) uses MTOM to encode the binary data and my server decodes it. Using MTOM allows the following struct members to be used,

struct _xop__Include
{ 
    unsigned char *__ptr;
    int __size;
    char *id;
    char *type;
    char *options;
};

I know what char *__ptr and __size are and how to use them. The id is randomly set by SoapUI but it can also be changed by the user, i.e. "cid:somename", and linked to the attachment accordingly. The type is already determined by SoapUI, and in my case "application/octet-stream".

How does SoapUI determine the type as "application/octet-stream" from my data. What is required for the options string in the struct. SoapUI doesn't seem to use it. Can it be set up in soapUI?

Thanks.