JPEG2000 transparency with JasPer library

I am trying to use the JasPer JPEG2000 library to create transparent JPEG2000 images (I am actually creating a JPC).

The problem I'm running into is that I can't figure out how to get JasPer to create a transparency image. None of the supported formats support transparency (except for the JPEG2000 formats I'm trying to create):

The following formats are supported:
    mif      My Image Format (MIF)
    pnm      Portable Graymap/Pixmap (PNM)
    bmp      Microsoft Bitmap (BMP)
    ras      Sun Rasterfile (RAS)
    jp2      JPEG-2000 JP2 File Format Syntax (ISO/IEC 15444-1)
    jpc      JPEG-2000 Code Stream Syntax (ISO/IEC 15444-1)
    jpg      JPEG (ISO/IEC 10918-1)
    pgx      JPEG-2000 VM Format (PGX)

      

        
        
        
      

    

The JasPer documentation uses the word "transparency" in this context:

An RGBA image (that is, RGB with transparency) will have four components, one of which is associated with each of the red, green, blue, and alpha planes. Different components do not have to be selected at the same resolution. In other words, different components can have different sampling periods. For example, when color images are represented in the luma-chroma color space, it is not uncommon for luma information to be more subtly sampled than chroma information.

This means that transparency is supported as it discusses how transparency works in encoding. And yet ... how to use it?

Any ideas?

Also, any other open source alternative that supports transparent JPC creation would be nice.

Thank.