T-SQL Syntax for SCD Type 2

[sauce1979]

I am currently trying to complete the final part of a query that loads scd type 2 data into a dimension.
Based on the data provided below I would like to produce an output that can be inserted into a dimension in addition to
expiring old records and tracking history etc. The data is such that I have the most current records where attributes have changed. The changed values are found in Lookup columns along with and dateOfchange i.e. the date the change took place. This dateOfchange should obviously become the validTo date of the most current record.

The sample data is as follows:

CREATE TABLE #tstDimPortfolio
(
	[ID][INT] IDENTITY (1,1) NOT NULL,
	[UPI] [varchar](20) NOT NULL,
	[MF_CODE] [varchar](10) NULL,
	[BH_Code] [varchar](10) NULL,
	[CR_Code] [varchar](10) NULL,
	[ValidFrom][varchar](10) NOT NULL,
	[ValidTo][varchar](10) NULL,
	[IsCurrent] [CHAR] (1) NULL,
	[DateofChange] [varchar](10) NULL,
	[LookupMF_CODE] [varchar](10) NULL,
	[LookupBH_Code] [varchar](10) NULL,
	[LookupCR_Code] [varchar](10) NULL,
	
	
) 

INSERT INTO #tstDimPortfolio
SELECT 'B06531','B06531','','B06531','20111230',NULL,'Y','20120101','','B06531', ''UNION ALL
SELECT 'BLI003','','BLI003','BBL_WORLD','20111230',NULL,'Y','20120102','BLI004','', ''UNION ALL 
SELECT 'BLI003','','BLI003','BBL_WORLD','20111230',NULL,'Y','20120103','BLI005','', ''UNION ALL 
SELECT 'BLI027','BLI027','L147','BBL_GBN','20111230',NULL,'Y','20120104','','L146', ''

With this data the new output should be

UPI	MF_CODE	  BH_Code  CR_Code   ValidFrom  ValidTo      IsCurrent
_______________________________________________________________________
B06531	B06531	B06531	             20111230   20120101  	N
B06531	B06531	B06531	B06531	     20120101	NULL	        Y
BLI003	BLI003	BBL_WORLD	       20111230	20120102        N
BLI003	BLI004	BLI003	BBL_WORLD    20120102	20120103 N
BLI003	BLI005	BLI003	BBL_WORLD    20120103	NULL	        Y
BLI027	BLI027	L147	       BBL_GBN	     20111230	20120104        N
BLI027	BLI027	L146	       BBL_GBN	     20120104	NULL	                Y