Data type not supported for HDL code generation when using Altera DSP builder blocks

Hi,

i am facing a problem when making a simulink model in which I use Altera DSP builder blocks. It simulates the model without any problems, but when I try to generate HDL code it gives me an error message such as : 'Data type 'INT_8' is not supported for HDL code generation'

and it does this for any data type.

Could anyone please help me??