This's all actually covered within the HJG B727 manual
See the "BOEING 727 MODEL ANIMATIONS" section .... within "SECTION 1.07" of the following-linked forum based HJH B727 manual ....https://tonymadgehjg.proboards.com/thre ... ling-notes
In any case the port side forward fuselage main deck cargo door on each of the HJG hosted B727-200 SCD type simulation function using the FS2004 "CONCORDE VISOR" keyboad commands .... which need to be "manually activated" within the "FS OPTIONS/CONTROLS/ASSIGNMENTS" section of FS2004.
PLEASE NOTE .... (1) Whilst the HJG B727 series "is" FSX portable (as are its panels too .... and separate FSX specific sound packs are also offered), these cargo doors "cannot function "in FSX" since the FSX based CONCORDE VISOR animation is controlled by "a diffrent combination of keyboard commands" which these models can't recognize .... and (2) whilst HJG "do" also offer B727-100 SCD type simulations too (with cargo specific W&B data), none of these models (again B727-100 SCD only) feature animated port side forward fuselage main deck cargo doors simply because that's the way these particular models were compiled and then supplied to HJG.
May I also suggest .... in future, and in regard to all HJG simulations, it's better to seek advice directly from the HJG forum .... since that's where the expertise which has either brought each of the HJG simulations into existence, or otherwise supports them, is located. This request is simply intended to ensure not only the best and most thorough, but also, the quickest resolutions for end users requiring assistance. It's not really practical for HJG to monitor all FS forums and provide support on each accordingly
I've only just seen/stumbled across this query here by "pure chance/accident"