I am quite sympathetic. All the different file formats for remote sensing data can be quite a challenge. I would check if GeoTiff's are available for this scene. Historically GeoTiff was the format GLCF distributed data in. As far as I can tell here is what your header (hdr) file should look like for bands 1-5 and 7 (will need a separate hdr file for each band).
Image BSQ header file
Here is the info I extracted from the metadata for the reflectance bands (1-5 & 7).
nrows - PRODUCT_SAMPLES_REF = 7871 (Can't remember if this is row or col)
ncols - PRODUCT_LINES_REF = 6951 (Can't remember if this is row or col)
ulxmap - PRODUCT_UL_CORNER_MAPX = 210000.000 (Looks like UTM coord for zone -20)
ulymap - PRODUCT_UL_CORNER_MAPY = 8505000.000 (Looks like UTM coord for zone -20)
xdim - GRID_CELL_SIZE_REF = 30.000000
ydim - GRID_CELL_SIZE_REF = 30.000000
Here is where it gets tricky. The data is band-sequential so when you import bands 6H, 6L (thermal) and 8 (panchromatic) you will need to change the header info to reflect different row,column dimensions and cell resolutions. The suffix in the metadata for bands 1-5 & 7 - "REF", for 6L and 6L - "THM", and band 8 - "PAN".
As soon as you get this working I would export each band into a grid and then use MAKESTACK (available in raster calculator) to make an image stack for multispectral viewing.