Using the modified version of IJG80b in IPP-Samples, normal non-prgressive saving of JPEGs works as expected. After calling jpeg_simple_progression to setup the progressive scan script the export appears to work, but the resulting JPEG is far to small and doesn't contain a valid image. I've confirm this behavour with a very simple test harness.
I wonder if the issue is there is an optimsed function (flush_bits_intellib) thats called in non-progressive case from finish_pass_huff, but no optimised function used in the progressive case. If the pass is built up in an internal buffer, not calling an intellib function may cause the compressed stream not to be written.