AN ACR B757 CREW; ALONG WITH HELP FROM ITS MAINT AND DISPATCH DEPTS; ATTEMPTED TO USE THE APU FOR BLEED AIR ABOVE ITS LIMITS WHILE OPERATING WITH ONE HIGH STAGE BLEED INOP. ERROR ADMITTED.

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ON TAXI FOR DEP; THE CAPT AND I RECOGNIZED LOW PNEUMATIC PRESSURE ON THE L SIDE (APPROX 5 PSI) WHICH CAUSED THE L PACK OFF LIGHT AND APPROPRIATE EICAS MESSAGE. MAINT WAS CONTACTED AND A RETURN TO THE GATE TO SECURE THE L ENG HIGH STAGE BLEED VALVE COMMENCED. THE MECH GREETING THE PLANE SUGGESTED ANOTHER WAY OF TURNING OFF THE ENG BLEED AIR. THIS WAS BY TURNING OFF THE ENG BLEED SWITCH ON THE PNEUMATIC PANEL IN THE COCKPIT. MAINT DISPATCH; AND THE FLC ALL CONFERRED TO OPERATE THE FLT UNDER THE LIMITATIONS CAUSED BY THE DEFERRED ITEM. (AUTH BY MEL). WE REQUESTED A NEW DISPATCH RELEASE TO ACCOUNT FOR THE INCREASED FUEL BURN AT FL250 AND TO REFLECT THE INOP BLEED AND PACK. A RELEASE WAS SENT WHICH INCLUDED THE FUEL BURN AT FL250; BUT THERE IS APPARENTLY NO MEL RESTRS FOR FLTS PLANNED BELOW FL350. SO; THE MEL NOTES WERE OMITTED FROM OUR FLT PLAN. DISPATCH RELAYED THAT THE ORIGINAL FLT PLAN AT FL330 WOULD STILL BE ACCEPTABLE. THE HEAT GENERATED BY THE ACFT SYS; ELECTRONICS; AND OUR PAX HAD RAISED THE TEMP OF THE CABIN TO ABOUT 94 DEGS. I CHKED THE FLT MANUAL TO FIND AN IRREGULAR PROC TO FOLLOW FOR DISPATCH WITH EITHER AN ENG BLEED INOP OR PACK INOP. BOTH OF THESE PROCS ARE LISTED TO SOLVE ENRTE SYS FAILURES; NOT PLANNING TO OPERATE THE ACFT COOLING AND PRESSURIZATION SYS INOP. THE CHKLISTS REFER TO KEEPING THE ISOLATION VALVE CLOSED (TO SEPARATE L AND R PNEUMATICS) UNLESS NECESSARY TO PROVIDE ANTI-ICE PROTECTION. THEY ALSO STATE THAT CABIN PRESSURIZATION SHOULD BE ABLE TO BE MAINTAINED UP TO AN ALT OF FL350. OUR FLT DEPARTED WITH THE HOPES THAT AT ALT THE CABIN TEMP WOULD COOL. ALL WENT WELL DURING THE INITIAL CLB. AT FL280 WE BEGAN TO BE CONCERNED THAT THE TEMP WAS STILL 92 DEGS. BOTH THE CAPT AND I THOUGHT TO START THE APU TO PROVIDE ADDITIONAL COOLING FROM THE L PACK. WHEN WE DID THIS; THE DUCT PRESSURE NEVER CHANGED. WE CONTINUED THE CLB TO FL330. UPON LEVEL OFF; WE NOTICED THE CABIN PRESSURE RISING AT ABOUT 1000 FPM. WE CONTINUED TO OBSERVE THIS AND THE RATE DECREASED TO 800 FPM AS THE CABIN PRESSURE ALT NEARED 9000 FT. I ASKED THE CAPT TO GET A DSCNT CLRNC IN CASE THE PRESSURIZATION DID NOT STOP CLBING. THE CLRNC WAS RECEIVED AND A DSCNT WAS INITIATED. IN THE DSCNT; (SPD BRAKES EXTENDED; THROTTLES AT THRUST TO GIVE PNEUMATIC PRESSURE) THE CABIN ALT WARNING HORN SOUNDED AS THE CABIN EXCEEDED 10000 FT. IN THE DSCNT; THE CABIN CORRECTED TO THE PROPER ALT; AND THE REMAINDER OF THE FLT WAS COMPLETED AT FL240. I FEEL THE FOLLOWING PROBS LED TO THE EVENTS MENTIONED: 1) LACK OF PNEUMATIC APU LIMITS LISTED IN THE FLT MANUAL. 2) LACK OF APPROPRIATE IRREGULAR PROCS FOR DISPATCH WITH BLEED OR PACK INOP CONDITION. 3) SLIGHT MISLEADING WORDING OF THE AIRPLANE MANUAL PNEUMATIC DESCRIPTION. 4) OUR CREW'S DELAY TO TAKE APPROPRIATE ACTION TO PREVENT THE RISE IN CABIN ALT. 5) OUR MISTAKES IN OP OF THE SECOND PNEUMATIC PACK. THIS REDUCED FLOW FROM THE OPERATING PACK. OUR APU WILL ONLY SUPPLY PNEUMATICS TO AN ALT OF ABOUT FL230; THUS THE LACK OF AIR TO THE SECOND PACK THAT WE TURNED ON IN FLT.