customer invoice pk- f-22 custo payment pk- f-28           
vendor invoice pk - f-43  vendor payment pk- f-53

Those r correct but they are not Pst.Kys but they are 
T.Codes.
The posting keys are Customer Invoice 01 & 50
For vendor Invoice are 31 & 40.

customer invoice             
01--customer invoice(debit)  ,pk 50--sales revenue
(credit  )                                                  
 customer payment    ;pk 40--cash/bank(debit),pk--15 
customer(credit),vendorinvoice  31-vendor (credit):pk 40--
purchases(debit):vendor payament pk40--vendor(debit)pk25--
cash\bank(credit)

Posting keys are

Customer debit-01,
Customer credit-15,
Vendor debit-25
Vendor Credit-31
GL debit-40,
GL credit-50.

For Customer Posting Key
PK	PARTICULARS		STATUS	DOC TYPE	PK
	PARTICULARS	DOC TYPE	STATUS
01	Invoice	Debit	Customer	DR/DA	12
	Reverse invoice	Credit	Customer
02	Reverse credit memo	Debit	Customer	DG
	11	Credit memo	Credit	Customer
03	Bank charges	Debit	Customer	DA	13
	Reverse charges	Credit	Customer
04	Other receivables	Debit	Customer	DZ
	14	Other payables	Credit	Customer
05	Outgoing payment	Debit	Customer	DZ
	15	Incoming payment	Credit	Customer
06	Payment difference	Debit	Customer	DA
	16	Payment difference	Credit	Customer
07	Other clearing	Debit	Customer	DZ	17
	Other clearing	Credit	Customer
08	Payment clearing	Debit	Customer	DZ
	18	Payment clearing	Credit	Customer
09	Special G/L debit	Debit	Customer	DR
	19	Special G/L credit	Credit	Customer

For Vendor Posting Key
31	Invoice	Credit	Vendor	KA/KR	22	Reverse 
invoice	Debit	Vendor
32	Reverse credit memo	Credit	Vendor	KG	21
	Credit memo	Debit	Vendor
34	Other payables	Credit	Vendor	KA/KR	24
	Other receivables	Debit	Vendor
35	Incoming payment	Credit	Vendor	KZ	25
	Outgoing payment	Debit	Vendor
36	Payment difference	Credit	Vendor	KZ	26
	Payment difference	Debit	Vendor
37	Other clearing	Credit	Vendor	KZ	27
	Clearing	Debit	Vendor
38	Payment clearing	Credit	Vendor	KZ	28
	Payment clearing	Debit	Vendor
39	Special G/L credit	Credit	Vendor	KR	29
	Special G/L debit	Debit	Vendor
40	Debit entry	Debit	G/L account	AB/SA	50
	Credit entry	Credit	G/L account

For Respective GL Posting 

Debit 40 GL Exp. /Vendor        
Crdit 50 for GL Income/Customer