Hello Raymond,
Thanks for your reply. I have already checked checked all the BAdIs that are triggered when the parked document is displayed/changed through transaction MIR4.
Here is the list of BAdIs. But unfortunately I cannot update the posting date through these BAdIs.
GOS_SRV_SELECT
PPA_CUST_BADI
ME_COMMITMENT_STO_CH
BADI_PRKNG_NO_UPDATE
FM_POP_CORE
MRM_PAYMENT_TERMS
MRM_WT_SPLIT_UPDATE
MRM_UDC_DISTRIBUTE
SD_COND_ACCESS_A
These 2 exits(EXIT_SAPLMR1M_003,EXIT_SAPLMR1M_001) are also of no use.