Context : In a previous work ( paper I ) a sample of 380 HMPO targets was studied using the GLIMPSE point source catalog and images .
Colour-magnitude analysis of the point sources resulted in the identification of infrared counterparts ( IRC ) of the ( sub ) mm cores of HMPO candidates which were considered bonafide targets .

Aims : We aim to estimate and analyse the physical properties of the infrared counterparts of HMPOs by comparing their spectral energy distributions ( SED ) with those predicted by radiative transfer accretion models of YSOs .

Methods : The SED of 68 IRC ’ s are extended beyond the GLIMPSE photometry to the possible limits , from the near-infrared to the millimetre wavelengths by using the 2MASS , GLIMPSE version 2.0 catalogs , MSX , IRAS and some single dish ( and interferometric ) ( sub ) mm data .
An online SED fitting tool that uses 2D radiative transfer accretion models of YSOs is employed to fit the observed SED to obtain various physical parameters .

Results : The SED of IRC ’ s were fitted by models of massive protostars with a range of masses between 5–42 M _ { \odot } and ages between 10 ^ { 3 } and 10 ^ { 6 } years .
The median mass and age are 10 M _ { \odot } and 10 ^ { 4 } yr ’ s .
The observed data favours protostars of low effective temperatures ( 4000-1000K ) with correspondingly large effective photospheres ( 2-200 R _ { \odot } ) for the observed luminosities .
The envelopes are large with a mean size of \sim 0.2-0.3 pc and show a distribution that is very similar to the distribution of the sizes of 8 \mu m nebulae discussed in Paper I .
The estimated envelope accretion rates are high with a mean value of 10 ^ { -3 } M _ { \odot } /yr and show a power law dependence to mass with an exponent of 2 , suggesting spherical accretion at those scales .
Disks are found to exist in most of the sources with a mean mass of 10 ^ { -1.4 \pm 0.7 } M _ { \odot } .

Conclusions : The observed infrared-millimetre SED of the infrared counterparts of HMPOs are successfully explained with an YSO accretion model .
The modelled sources mostly represent proto-B stars although some of them could become O stars in future .
We demonstrate that many of these results may represent a realistic picture of massive star formation , despite some of the results which may be an effect of the assumptions within the models .