array data to XML in C

Question

I'm working on LPC 1768 with KEIL IDE . And I want to send a array of the char to client side as a XML file . but when I get them on the client side , datas changed ! in server side we have 20,000 bytes(char) of data which I have to send client side them.

Here is server code: At here I fill in buffer with datas for sending

    for(fill_loop=0;fill_loop<20000;++fill_loop)
    {
      char_temp = Spi_Flash_read_byte(fill_loop+300);
      /*makes numbers to string*/
      len=sprintf(strReport,"%c",(unsigned char)char_temp);                              
      strcat(str_temp,strReport);
    }

And this is a XML file format:

t <form>
t <text>
t <id>parameters</id>
c X 1<value>%s</value>
t </text>
t </form>
.

How can I fix it? And where is my wrong?