Pierre-Yves,
Two independent suggestions:
1. Edit the linker .cmd file to assign .cinit to SDRAM. This is the section that holds those initialization values.
2. Try the RAM model in the compiler/linker tools. I believe it is -cr, but I can never remember well the particulars between -c and -cr.
You may also want to consider an algorithmic method of initializing the array. If it is a pattern that can be generated by a small equation, that could save a lot of memory for initialization.
Regards,
RandyP