Initialize a Structure that Contains an Array within a Macro in C

I am writing some code for an MSP430 project and am having some trouble initializing a structure within a macro. The structure is a buffer structure:

struct Buffer{
    unsigned int size;
    unsigned int start;
    unsigned int end;
    unsigned int count;
    unsigned char *data;
};

void buffer_init(struct Buffer *buffer, unsigned char *buffer_data, unsigned int size)
{
    buffer->size  = size;
    buffer->start = 0;
    buffer->end = 0;
    buffer->count = 0;
    buffer->data = buffer_data;
}

I have been having good luck with creating and initializing an array as follows (where the array is placed in a certain section in memory):

struct Buffer stream1_buffer;
#pragma DATA_SECTION(stream1_buffer_data, ".fram_vars")
static unsigned char stream1_buffer_data[512];

void init(void) {
    buffer_init(&stream1_buffer,stream1_buffer_data,sizeof(stream1_buffer_data));
}

However, I need to now create an array of variable sized buffers that have a bit more information, such as channel number and sample rate. So I would like to be able to initialize a buffer in a macro so that I can easily create an array of a new structure called Stream that contains a buffer.

I have tried the following, but the test code does not provide the same results as it did when I initialized the buffer structure normally.

#define def_Buffer(name,length) \
    static unsigned char name##_buffer_data[length]; \
    static struct Buffer name##_buffer = { \
        .size=length, \
        .start=0, \
        .end=0, \
        .count=0, \
        .data=(unsigned char *) name##_buffer_data \
    }

Any suggestions on how to proceed? I'm not even 100% sure this is good coding practice. Thanks!